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2025-09-04Revert "drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS"Imre Deak1-1/+1
This reverts commit 4f546a77671076a0a49c08b4c6a7d0888d72f7d2 which is commit a40c5d727b8111b5db424a1e43e14a1dcce1e77f upstream. The upstream commit a40c5d727b8111b5db424a1e43e14a1dcce1e77f ("drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS") the reverted commit backported causes a regression, on one eDP panel at least resulting in display flickering, described in detail at the Link: below. The issue fixed by the upstream commit will need a different solution, revert the backport for now. Cc: intel-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: Sasha Levin <sashal@kernel.org> Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14558 Signed-off-by: Imre Deak <imre.deak@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-08-28drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUSImre Deak1-1/+1
[ Upstream commit a40c5d727b8111b5db424a1e43e14a1dcce1e77f ] Reading DPCD registers has side-effects in general. In particular accessing registers outside of the link training register range (0x102-0x106, 0x202-0x207, 0x200c-0x200f, 0x2216) is explicitly forbidden by the DP v2.1 Standard, see 3.6.5.1 DPTX AUX Transaction Handling Mandates 3.6.7.4 128b/132b DP Link Layer LTTPR Link Training Mandates Based on my tests, accessing the DPCD_REV register during the link training of an UHBR TBT DP tunnel sink leads to link training failures. Solve the above by using the DP_LANE0_1_STATUS (0x202) register for the DPCD register access quirk. Cc: <stable@vger.kernel.org> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://lore.kernel.org/r/20250605082850.65136-2-imre.deak@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-10drm/dp_mst: Fix drm RAD printWayne Lin1-4/+4
[ Upstream commit 6bbce873a9c97cb12f5455c497be279ac58e707f ] [Why] The RAD of sideband message printed today is incorrect. For RAD stored within MST branch - If MST branch LCT is 1, it's RAD array is untouched and remained as 0. - If MST branch LCT is larger than 1, use nibble to store the up facing port number in cascaded sequence as illustrated below: u8 RAD[0] = (LCT_2_UFP << 4) | LCT_3_UFP RAD[1] = (LCT_4_UFP << 4) | LCT_5_UFP ... In drm_dp_mst_rad_to_str(), it wrongly to use BIT_MASK(4) to fetch the port number of one nibble. [How] Adjust the code by: - RAD array items are valuable only for LCT >= 1. - Use 0xF as the mask to replace BIT_MASK(4) V2: - Document how RAD is constructed (Imre) V3: - Adjust the comment for rad[] so kdoc formats it properly (Lyude) Fixes: 2f015ec6eab6 ("drm/dp_mst: Add sideband down request tracing + selftests") Cc: Imre Deak <imre.deak@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Harry Wentland <hwentlan@amd.com> Cc: Lyude Paul <lyude@redhat.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20250113091100.3314533-2-Wayne.Lin@amd.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-03-28drm/dp_mst: Fix locking when skipping CSN before topology probingImre Deak1-16/+24
commit 12d8f318347b1d4feac48e8ac351d3786af39599 upstream. The handling of the MST Connection Status Notify message is skipped if the probing of the topology is still pending. Acquiring the drm_dp_mst_topology_mgr::probe_lock for this in drm_dp_mst_handle_up_req() is problematic: the task/work this function is called from is also responsible for handling MST down-request replies (in drm_dp_mst_handle_down_rep()). Thus drm_dp_mst_link_probe_work() - holding already probe_lock - could be blocked waiting for an MST down-request reply while drm_dp_mst_handle_up_req() is waiting for probe_lock while processing a CSN message. This leads to the probe work's down-request message timing out. A scenario similar to the above leading to a down-request timeout is handling a CSN message in drm_dp_mst_handle_conn_stat(), holding the probe_lock and sending down-request messages while a second CSN message sent by the sink subsequently is handled by drm_dp_mst_handle_up_req(). Fix the above by moving the logic to skip the CSN handling to drm_dp_mst_process_up_req(). This function is called from a work (separate from the task/work handling new up/down messages), already holding probe_lock. This solves the above timeout issue, since handling of down-request replies won't be blocked by probe_lock. Fixes: ddf983488c3e ("drm/dp_mst: Skip CSN if topology probing is not done yet") Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Lyude Paul <lyude@redhat.com> Cc: stable@vger.kernel.org # v6.6+ Reviewed-by: Wayne Lin <Wayne.Lin@amd.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20250307183152.3822170-1-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-21gpu: drm_dp_cec: fix broken CEC adapter properties checkHans Verkuil1-11/+3
[ Upstream commit 6daaae5ff7f3b23a2dacc9c387ff3d4f95b67cad ] If the hotplug detect of a display is low for longer than one second (configurable through drm_dp_cec_unregister_delay), then the CEC adapter is unregistered since we assume the display was disconnected. If the HPD went low for less than one second, then we check if the properties of the CEC adapter have changed, since that indicates that we actually switch to new hardware and we have to unregister the old CEC device and register a new one. Unfortunately, the test for changed properties was written poorly, and after a new CEC capability was added to the CEC core code the test always returned true (i.e. the properties had changed). As a result the CEC device was unregistered and re-registered for every HPD toggle. If the CEC remote controller integration was also enabled (CONFIG_MEDIA_CEC_RC was set), then the corresponding input device was also unregistered and re-registered. As a result the input device in /sys would keep incrementing its number, e.g.: /sys/devices/pci0000:00/0000:00:08.1/0000:e7:00.0/rc/rc0/input20 Since short HPD toggles are common, the number could over time get into the thousands. While not a serious issue (i.e. nothing crashes), it is not intended to work that way. This patch changes the test so that it only checks for the single CEC capability that can actually change, and it ignores any other capabilities, so this is now safe as well if new caps are added in the future. With the changed test the bit under #ifndef CONFIG_MEDIA_CEC_RC can be dropped as well, so that's a nice cleanup. Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl> Reported-by: Farblos <farblos@vodafonemail.de> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Fixes: 2c6d1fffa1d9 ("drm: add support for DisplayPort CEC-Tunneling-over-AUX") Tested-by: Farblos <farblos@vodafonemail.de> Link: https://patchwork.freedesktop.org/patch/msgid/361bb03d-1691-4e23-84da-0861ead5dbdc@xs4all.nl Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-01-02drm/dp_mst: Ensure mst_primary pointer is valid in drm_dp_mst_handle_up_req()Imre Deak1-6/+18
[ Upstream commit e54b00086f7473dbda1a7d6fc47720ced157c6a8 ] While receiving an MST up request message from one thread in drm_dp_mst_handle_up_req(), the MST topology could be removed from another thread via drm_dp_mst_topology_mgr_set_mst(false), freeing mst_primary and setting drm_dp_mst_topology_mgr::mst_primary to NULL. This could lead to a NULL deref/use-after-free of mst_primary in drm_dp_mst_handle_up_req(). Avoid the above by holding a reference for mst_primary in drm_dp_mst_handle_up_req() while it's used. v2: Fix kfreeing the request if getting an mst_primary reference fails. Cc: Lyude Paul <lyude@redhat.com> Reviewed-by: Lyude Paul <lyude@redhat.com> (v1) Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241204132007.3132494-1-imre.deak@intel.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14drm/display: Fix building with GCC 15Brahmajit Das1-2/+2
[ Upstream commit a500f3751d3c861be7e4463c933cf467240cca5d ] GCC 15 enables -Werror=unterminated-string-initialization by default. This results in the following build error drivers/gpu/drm/display/drm_dp_dual_mode_helper.c: In function ‘is_hdmi_adaptor’: drivers/gpu/drm/display/drm_dp_dual_mode_helper.c:164:17: error: initializer-string for array of ‘char’ is too long [-Werror=unterminated-string-initialization] 164 | "DP-HDMI ADAPTOR\x04"; | ^~~~~~~~~~~~~~~~~~~~~ After discussion with Ville, the fix was to increase the size of dp_dual_mode_hdmi_id array by one, so that it can accommodate the NULL line character. This should let us build the kernel with GCC 15. Signed-off-by: Brahmajit Das <brahmajit.xyz@gmail.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241002092311.942822-1-brahmajit.xyz@gmail.com Signed-off-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14drm/dp_mst: Fix resetting msg rx state after topology removalImre Deak1-2/+19
commit a6fa67d26de385c3c7a23c1e109a0e23bfda4ec7 upstream. If the MST topology is removed during the reception of an MST down reply or MST up request sideband message, the drm_dp_mst_topology_mgr::up_req_recv/down_rep_recv states could be reset from one thread via drm_dp_mst_topology_mgr_set_mst(false), racing with the reading/parsing of the message from another thread via drm_dp_mst_handle_down_rep() or drm_dp_mst_handle_up_req(). The race is possible since the reader/parser doesn't hold any lock while accessing the reception state. This in turn can lead to a memory corruption in the reader/parser as described by commit bd2fccac61b4 ("drm/dp_mst: Fix MST sideband message body length check"). Fix the above by resetting the message reception state if needed before reading/parsing a message. Another solution would be to hold the drm_dp_mst_topology_mgr::lock for the whole duration of the message reception/parsing in drm_dp_mst_handle_down_rep() and drm_dp_mst_handle_up_req(), however this would require a bigger change. Since the fix is also needed for stable, opting for the simpler solution in this patch. Cc: Lyude Paul <lyude@redhat.com> Cc: <stable@vger.kernel.org> Fixes: 1d082618bbf3 ("drm/display/dp_mst: Fix down/up message handling after sink disconnect") Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13056 Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241203160223.2926014-2-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14drm/dp_mst: Verify request type in the corresponding down message replyImre Deak1-0/+31
commit 4d49e77a973d3b5d1881663c3f122906a0702940 upstream. After receiving the response for an MST down request message, the response should be accepted/parsed only if the response type matches that of the request. Ensure this by checking if the request type code stored both in the request and the reply match, dropping the reply in case of a mismatch. This fixes the topology detection for an MST hub, as described in the Closes link below, where the hub sends an incorrect reply message after a CLEAR_PAYLOAD_TABLE -> LINK_ADDRESS down request message sequence. Cc: Lyude Paul <lyude@redhat.com> Cc: <stable@vger.kernel.org> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/12804 Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241203160223.2926014-3-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14drm/dp_mst: Fix MST sideband message body length checkImre Deak1-0/+3
commit bd2fccac61b40eaf08d9546acc9fef958bfe4763 upstream. Fix the MST sideband message body length check, which must be at least 1 byte accounting for the message body CRC (aka message data CRC) at the end of the message. This fixes a case where an MST branch device returns a header with a correct header CRC (indicating a correctly received body length), with the body length being incorrectly set to 0. This will later lead to a memory corruption in drm_dp_sideband_append_payload() and the following errors in dmesg: UBSAN: array-index-out-of-bounds in drivers/gpu/drm/display/drm_dp_mst_topology.c:786:25 index -1 is out of range for type 'u8 [48]' Call Trace: drm_dp_sideband_append_payload+0x33d/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] memcpy: detected field-spanning write (size 18446744073709551615) of single field "&msg->msg[msg->curlen]" at drivers/gpu/drm/display/drm_dp_mst_topology.c:791 (size 256) Call Trace: drm_dp_sideband_append_payload+0x324/0x350 [drm_display_helper] drm_dp_get_one_sb_msg+0x3ce/0x5f0 [drm_display_helper] drm_dp_mst_hpd_irq_handle_event+0xc8/0x1580 [drm_display_helper] Cc: <stable@vger.kernel.org> Cc: Lyude Paul <lyude@redhat.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20241125205314.1725887-1-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-14drm/dp_mst: Skip CSN if topology probing is not done yetWayne Lin1-0/+11
commit ddf983488c3e8d30d5c2e2b315ae7d9cd87096ed upstream. [Why] During resume, observe that we receive CSN event before we start topology probing. Handling CSN at this moment based on uncertain topology is unnecessary. [How] Add checking condition in drm_dp_mst_handle_up_req() to skip handling CSN if the topology is yet to be probed. Cc: Lyude Paul <lyude@redhat.com> Cc: Harry Wentland <hwentlan@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: stable@vger.kernel.org Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240626084825.878565-3-Wayne.Lin@amd.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-08-03drm/dp_mst: Fix all mstb marked as not probed after suspend/resumeWayne Lin1-2/+2
commit d63d81094d208abb20fc444514b2d9ec2f4b7c4e upstream. [Why] After supend/resume, with topology unchanged, observe that link_address_sent of all mstb are marked as false even the topology probing is done without any error. It is caused by wrongly also include "ret == 0" case as a probing failure case. [How] Remove inappropriate checking conditions. Cc: Lyude Paul <lyude@redhat.com> Cc: Harry Wentland <hwentlan@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel@ffwll.ch> Cc: stable@vger.kernel.org Fixes: 37dfdc55ffeb ("drm/dp_mst: Cleanup drm_dp_send_link_address() a bit") Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20240626084825.878565-2-Wayne.Lin@amd.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-06-12drm/dp: Don't attempt AUX transfers when eDP panels are not poweredDouglas Anderson1-0/+35
[ Upstream commit 8df1ddb5bf11ab820ad991e164dab82c0960add9 ] If an eDP panel is not powered on then any attempts to talk to it over the DP AUX channel will timeout. Unfortunately these attempts may be quite slow. Userspace can initiate these attempts either via a /dev/drm_dp_auxN device or via the created i2c device. Making the DP AUX drivers timeout faster is a difficult proposition. In theory we could just poll the panel's HPD line in the AUX transfer function and immediately return an error there. However, this is easier said than done. For one thing, there's no hard requirement to hook the HPD line up for eDP panels and it's OK to just delay a fixed amount. For another thing, the HPD line may not be fast to probe. On parade-ps8640 we need to wait for the bridge chip's firmware to boot before we can get the HPD line and this is a slow process. The fact that the transfers are taking so long to timeout is causing real problems. The open source fwupd daemon sometimes scans DP busses looking for devices whose firmware need updating. If it happens to scan while a panel is turned off this scan can take a long time. The fwupd daemon could try to be smarter and only scan when eDP panels are turned on, but we can also improve the behavior in the kernel. Let's let eDP panels drivers specify that a panel is turned off and then modify the common AUX transfer code not to attempt a transfer in this case. Tested-by: Steev Klimaszewski <steev@kali.org> Reviewed-by: Hsin-Yi Wang <hsinyi@chromium.org> Tested-by: Eizan Miyamoto <eizan@chromium.org> Acked-by: Neil Armstrong <neil.armstrong@linaro.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20240202141109.1.I24277520ac754ea538c9b14578edc94e1df11b48@changeid Stable-dep-of: 5e842d55bad7 ("drm/panel: atna33xc20: Fix unbalanced regulator in the case HPD doesn't assert") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-02drm/dp_mst: Fix NULL deref in get_mst_branch_device_by_guid_helper()Lukasz Majczak1-3/+3
commit 3d887d512494d678b17c57b835c32f4e48d34f26 upstream. As drm_dp_get_mst_branch_device_by_guid() is called from drm_dp_get_mst_branch_device_by_guid(), mstb parameter has to be checked, otherwise NULL dereference may occur in the call to the memcpy() and cause following: [12579.365869] BUG: kernel NULL pointer dereference, address: 0000000000000049 [12579.365878] #PF: supervisor read access in kernel mode [12579.365880] #PF: error_code(0x0000) - not-present page [12579.365882] PGD 0 P4D 0 [12579.365887] Oops: 0000 [#1] PREEMPT SMP NOPTI ... [12579.365895] Workqueue: events_long drm_dp_mst_up_req_work [12579.365899] RIP: 0010:memcmp+0xb/0x29 [12579.365921] Call Trace: [12579.365927] get_mst_branch_device_by_guid_helper+0x22/0x64 [12579.365930] drm_dp_mst_up_req_work+0x137/0x416 [12579.365933] process_one_work+0x1d0/0x419 [12579.365935] worker_thread+0x11a/0x289 [12579.365938] kthread+0x13e/0x14f [12579.365941] ? process_one_work+0x419/0x419 [12579.365943] ? kthread_blkcg+0x31/0x31 [12579.365946] ret_from_fork+0x1f/0x30 As get_mst_branch_device_by_guid_helper() is recursive, moving condition to the first line allow to remove a similar one for step over of NULL elements inside a loop. Fixes: 5e93b8208d3c ("drm/dp/mst: move GUID storage from mgr, port to only mst branch") Cc: <stable@vger.kernel.org> # 4.14+ Signed-off-by: Lukasz Majczak <lma@semihalf.com> Reviewed-by: Radoslaw Biernacki <rad@chromium.org> Signed-off-by: Manasi Navare <navaremanasi@chromium.org> Link: https://patchwork.freedesktop.org/patch/msgid/20230922063410.23626-1-lma@semihalf.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-27drm/dp_mst: Clear MSG_RDY flag before sending new messageWayne Lin1-7/+47
commit 72f1de49ffb90b29748284f27f1d6b829ab1de95 upstream. [Why] The sequence for collecting down_reply from source perspective should be: Request_n->repeat (get partial reply of Request_n->clear message ready flag to ack DPRX that the message is received) till all partial replies for Request_n are received->new Request_n+1. Now there is chance that drm_dp_mst_hpd_irq() will fire new down request in the tx queue when the down reply is incomplete. Source is restricted to generate interveleaved message transactions so we should avoid it. Also, while assembling partial reply packets, reading out DPCD DOWN_REP Sideband MSG buffer + clearing DOWN_REP_MSG_RDY flag should be wrapped up as a complete operation for reading out a reply packet. Kicking off a new request before clearing DOWN_REP_MSG_RDY flag might be risky. e.g. If the reply of the new request has overwritten the DPRX DOWN_REP Sideband MSG buffer before source writing one to clear DOWN_REP_MSG_RDY flag, source then unintentionally flushes the reply for the new request. Should handle the up request in the same way. [How] Separete drm_dp_mst_hpd_irq() into 2 steps. After acking the MST IRQ event, driver calls drm_dp_mst_hpd_irq_send_new_request() and might trigger drm_dp_mst_kick_tx() only when there is no on going message transaction. Changes since v1: * Reworked on review comments received -> Adjust the fix to let driver explicitly kick off new down request when mst irq event is handled and acked -> Adjust the commit message Changes since v2: * Adjust the commit message * Adjust the naming of the divided 2 functions and add a new input parameter "ack". * Adjust code flow as per review comments. Changes since v3: * Update the function description of drm_dp_mst_hpd_irq_handle_event Changes since v4: * Change ack of drm_dp_mst_hpd_irq_handle_event() to be an array align the size of esi[] Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-07-19drm: use mgr->dev in drm_dbg_kms in drm_dp_add_payload_part2Jeff Layton1-1/+1
commit 54d217406afe250d7a768783baaa79a035f21d38 upstream. I've been experiencing some intermittent crashes down in the display driver code. The symptoms are ususally a line like this in dmesg: amdgpu 0000:30:00.0: [drm] Failed to create MST payload for port 000000006d3a3885: -5 ...followed by an Oops due to a NULL pointer dereference. Switch to using mgr->dev instead of state->dev since "state" can be NULL in some cases. Link: https://bugzilla.redhat.com/show_bug.cgi?id=2184855 Suggested-by: Jani Nikula <jani.nikula@linux.intel.com> Signed-off-by: Jeff Layton <jlayton@kernel.org> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230419112447.18471-1-jlayton@kernel.org Cc: "Limonciello, Mario" <mario.limonciello@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-04-13drm/display/dp_mst: Handle old/new payload states in drm_dp_remove_payload()Imre Deak1-12/+14
commit e761cc20946a0094df71cb31a565a6a0d03bd8be upstream. Atm, drm_dp_remove_payload() uses the same payload state to both get the vc_start_slot required for the payload removal DPCD message and to deduct time_slots from vc_start_slot of all payloads after the one being removed. The above isn't always correct, as vc_start_slot must be the up-to-date version contained in the new payload state, but time_slots must be the one used when the payload was previously added, contained in the old payload state. The new payload's time_slots can change vs. the old one if the current atomic commit changes the corresponding mode. This patch let's drivers pass the old and new payload states to drm_dp_remove_payload(), but keeps these the same for now in all drivers not to change the behavior. A follow-up i915 patch will pass in that driver the correct old and new states to the function. Cc: Lyude Paul <lyude@redhat.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Karol Herbst <kherbst@redhat.com> Cc: Harry Wentland <harry.wentland@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: stable@vger.kernel.org # 6.1 Cc: dri-devel@lists.freedesktop.org Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Acked-by: Lyude Paul <lyude@redhat.com> Acked-by: Daniel Vetter <daniel@ffwll.ch> Acked-by: Wayne Lin <wayne.lin@amd.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230206114856.2665066-2-imre.deak@intel.com Hand modified for missing 8c7d980da9ba3eb67a1b40fd4b33bcf49397084b Signed-off-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-17drm/display: Don't block HDR_OUTPUT_METADATA on unknown EOTFHarry Wentland1-4/+2
commit e5eef23e267c72521d81f23f7f82d1f523d4a253 upstream. The EDID of an HDR display defines EOTFs that are supported by the display and can be set in the HDR metadata infoframe. Userspace is expected to read the EDID and set an appropriate HDR_OUTPUT_METADATA. In drm_parse_hdr_metadata_block the kernel reads the supported EOTFs from the EDID and stores them in the drm_connector->hdr_sink_metadata. While doing so it also filters the EOTFs to the EOTFs the kernel knows about. When an HDR_OUTPUT_METADATA is set it then checks to make sure the EOTF is a supported EOTF. In cases where the kernel doesn't know about a new EOTF this check will fail, even if the EDID advertises support. Since it is expected that userspace reads the EDID to understand what the display supports it doesn't make sense for DRM to block an HDR_OUTPUT_METADATA if it contains an EOTF the kernel doesn't understand. This comes with the added benefit of future-proofing metadata support. If the spec defines a new EOTF there is no need to update DRM and an compositor can immediately make use of it. Bug: https://gitlab.freedesktop.org/wayland/weston/-/issues/609 v2: Distinguish EOTFs defind in kernel and ones defined in EDID in the commit description (Pekka) v3: Rebase; drm_hdmi_infoframe_set_hdr_metadata moved to drm_hdmi_helper.c Signed-off-by: Harry Wentland <harry.wentland@amd.com> Cc: Pekka Paalanen <ppaalanen@gmail.com> Cc: Sebastian Wick <sebastian.wick@redhat.com> Cc: Vitaly.Prosyak@amd.com Cc: Uma Shankar <uma.shankar@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Joshua Ashton <joshua@froggi.es> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: dri-devel@lists.freedesktop.org Cc: amd-gfx@lists.freedesktop.org Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com> Reviewed-By: Joshua Ashton <joshua@froggi.es> Link: https://patchwork.freedesktop.org/patch/msgid/20230113162428.33874-2-harry.wentland@amd.com Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11drm/display/dp_mst: Fix payload addition on a disconnected sinkImre Deak1-1/+6
commit 33f960e23c29d113fe3193e0bdc19ac4f3776f20 upstream. If an MST stream is enabled on a disconnected sink, the payload for the stream is not created and the MST manager's payload count/next start VC slot is not updated. Since the payload's start VC slot may still contain a valid value (!= -1) the subsequent disabling of such a stream could cause an incorrect decrease of the payload count/next start VC slot in drm_dp_remove_payload() and hence later payload additions will fail. Fix the above by marking the payload as invalid in the above case, so that it's skipped during payload removal. While at it add a debug print for this case. Cc: Lyude Paul <lyude@redhat.com> Cc: <stable@vger.kernel.org> # v6.1+ Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-3-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11drm/display/dp_mst: Fix down message handling after a packet reception errorImre Deak1-1/+1
commit 1241aedb6b5c7a5a8ad73e5eb3a41cfe18a3e00e upstream. After an error during receiving a packet for a multi-packet DP MST sideband message, the state tracking which packets have been received already is not reset. This prevents the reception of subsequent down messages (due to the pending message not yet completed with an end-of-message-transfer packet). Fix the above by resetting the reception state after a packet error. Cc: Lyude Paul <lyude@redhat.com> Cc: <stable@vger.kernel.org> # v3.17+ Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-2-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11drm/display/dp_mst: Fix down/up message handling after sink disconnectImre Deak1-0/+3
commit 1d082618bbf3b6755b8cc68c0a8122af2842d593 upstream. If the sink gets disconnected during receiving a multi-packet DP MST AUX down-reply/up-request sideband message, the state keeping track of which packets have been received already is not reset. This results in a failed sanity check for the subsequent message packet received after a sink is reconnected (due to the pending message not yet completed with an end-of-message-transfer packet), indicated by the "sideband msg set header failed" error. Fix the above by resetting the up/down message reception state after a disconnect event. Cc: Lyude Paul <lyude@redhat.com> Cc: <stable@vger.kernel.org> # v3.17+ Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221214184258.2869417-1-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-03-11drm/display/dp_mst: Add drm_atomic_get_old_mst_topology_state()Imre Deak1-4/+29
commit 9ffdb67af0ee625ae127711845532f670cc6a4e7 upstream. Add a function to get the old MST topology state, required by a follow-up i915 patch. While at it clarify the code comment of drm_atomic_get_new_mst_topology_state() and add _new prefix to the new state pointer to remind about its difference from the old state. v2: Use old_/new_ prefixes for the state pointers. (Ville) Cc: Lyude Paul <lyude@redhat.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: stable@vger.kernel.org # 6.1 Cc: dri-devel@lists.freedesktop.org Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Acked-by: Lyude Paul <lyude@redhat.com> Acked-by: Daniel Vetter <daniel@ffwll.ch> Acked-by: Wayne Lin <wayne.lin@amd.com> Acked-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230206114856.2665066-3-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-02-01drm/display/dp_mst: Correct the kref of port.Wayne Lin1-1/+3
commit d8bf2df715bb8ac964f91fe8bf67c37c5d916463 upstream. [why & how] We still need to refer to port while removing payload at commit_tail. we should keep the kref till then to release. Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2171 Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> Signed-off-by: Harry Wentland <harry.wentland@amd.com> Fixes: 4d07b0bc4034 ("drm/display/dp_mst: Move all payload info into the atomic state") Cc: stable@vger.kernel.org # 6.1 Acked-by: Harry Wentland <harry.wentland@amd.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Tested-by: Didier Raboud <odyx@debian.org> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-11-22drm/display/dp_mst: Fix drm_dp_mst_add_affected_dsc_crtcs() return codeLyude Paul1-1/+1
Looks like that we're accidentally dropping a pretty important return code here. For some reason, we just return -EINVAL if we fail to get the MST topology state. This is wrong: error codes are important and should never be squashed without being handled, which here seems to have the potential to cause a deadlock. Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Wayne Lin <Wayne.Lin@amd.com> Fixes: 8ec046716ca8 ("drm/dp_mst: Add helper to trigger modeset on affected DSC MST CRTCs") Cc: <stable@vger.kernel.org> # v5.6+ Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2022-11-16drm/display: Don't assume dual mode adaptors support i2c sub-addressingSimon Rettberg1-22/+29
Current dual mode adaptor ("DP++") detection code assumes that all adaptors support i2c sub-addressing for read operations from the DP-HDMI adaptor ID buffer. It has been observed that multiple adaptors do not in fact support this, and always return data starting at register 0. On affected adaptors, the code fails to read the proper registers that would identify the device as a type 2 adaptor, and handles those as type 1, limiting the TMDS clock to 165MHz, even if the according register would announce a higher TMDS clock. Fix this by always reading the ID buffer starting from offset 0, and discarding any bytes before the actual offset of interest. We tried finding authoritative documentation on whether or not this is allowed behaviour, but since all the official VESA docs are paywalled, the best we could come up with was the spec sheet for Texas Instruments' SNx5DP149 chip family.[1] It explicitly mentions that sub-addressing is supported for register writes, but *not* for reads (See NOTE in section 8.5.3). Unless TI openly decided to violate the VESA spec, one could take that as a hint that sub-addressing is in fact not mandated by VESA. The other two adaptors affected used the PS8409(A) and the LT8611, according to the data returned from their ID buffers. [1] https://www.ti.com/lit/ds/symlink/sn75dp149.pdf Cc: stable@vger.kernel.org Signed-off-by: Simon Rettberg <simon.rettberg@rz.uni-freiburg.de> Reviewed-by: Rafael Gieschke <rafael.gieschke@rz.uni-freiburg.de> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221006113314.41101987@computer Acked-by: Jani Nikula <jani.nikula@intel.com>
2022-10-08Merge tag 'driver-core-6.1-rc1' of ↵Linus Torvalds1-0/+13
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core Pull driver core updates from Greg KH: "Here is the big set of driver core and debug printk changes for 6.1-rc1. Included in here is: - dynamic debug updates for the core and the drm subsystem. The drm changes have all been acked by the relevant maintainers - kernfs fixes for syzbot reported problems - kernfs refactors and updates for cgroup requirements - magic number cleanups and removals from the kernel tree (they were not being used and they really did not actually do anything) - other tiny cleanups All of these have been in linux-next for a while with no reported issues" * tag 'driver-core-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (74 commits) docs: filesystems: sysfs: Make text and code for ->show() consistent Documentation: NBD_REQUEST_MAGIC isn't a magic number a.out: restore CMAGIC device property: Add const qualifier to device_get_match_data() parameter drm_print: add _ddebug descriptor to drm_*dbg prototypes drm_print: prefer bare printk KERN_DEBUG on generic fn drm_print: optimize drm_debug_enabled for jump-label drm-print: add drm_dbg_driver to improve namespace symmetry drm-print.h: include dyndbg header drm_print: wrap drm_*_dbg in dyndbg descriptor factory macro drm_print: interpose drm_*dbg with forwarding macros drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers. drm_print: condense enum drm_debug_category debugfs: use DEFINE_SHOW_ATTRIBUTE to define debugfs_regset32_fops driver core: use IS_ERR_OR_NULL() helper in device_create_groups_vargs() Documentation: ENI155_MAGIC isn't a magic number Documentation: NBD_REPLY_MAGIC isn't a magic number nbd: remove define-only NBD_MAGIC, previously magic number Documentation: FW_HEADER_MAGIC isn't a magic number Documentation: EEPROM_MAGIC_VALUE isn't a magic number ...
2022-09-28drm/dp: Don't rewrite link config when setting phy test patternKhaled Almahallawy1-9/+0
The sequence for Source DP PHY CTS automation is [2][1]: 1- Emulate successful Link Training(LT) 2- Short HPD and change link rates and number of lanes by LT. (This is same flow for Link Layer CTS) 3- Short HPD and change PHY test pattern and swing/pre-emphasis levels (This step should not trigger LT) The problem is with DP PHY compliance setup as follow: [DPTX + on board LTTPR]------Main Link--->[Scope] ^ | | | | | ----------Aux Ch------>[Aux Emulator] At step 3, before writing TRAINING_LANEx_SET/LINK_QUAL_PATTERN_SET to declare the pattern/swing requested by scope, we write link config in LINK_BW_SET/LANE_COUNT_SET on a port that has LTTPR. As LTTPR snoops aux transaction, LINK_BW_SET/LANE_COUNT_SET writes indicate a LT will start [Check DP 2.0 E11 -Sec 3.6.8.2 & 3.6.8.6.3], and LTTPR will reset the link and stop sending DP signals to DPTX/Scope causing the measurements to fail. Note that step 3 will not trigger LT and DP link will never recovered by the Aux Emulator/Scope. The reset of link can be tested with a monitor connected to LTTPR port simply by writing to LINK_BW_SET or LANE_COUNT_SET as follow igt/tools/dpcd_reg write --offset=0x100 --value 0x14 --device=2 OR printf '\x14' | sudo dd of=/dev/drm_dp_aux2 bs=1 count=1 conv=notrunc seek=$((0x100)) This single aux write causes the screen to blank, sending short HPD to DPTX, setting LINK_STATUS_UPDATE = 1 in DPCD 0x204, and triggering LT. As stated in [1]: "Before any TX electrical testing can be performed, the link between a DPTX and DPRX (in this case, a piece of test equipment), including all LTTPRs within the path, shall be trained as defined in this Standard." In addition, changing Phy pattern/Swing/Pre-emphasis (Step 3) uses the same link rate and lane count applied on step 2, so no need to redo LT. The fix is to not rewrite link config in step 3, and just writes TRAINING_LANEx_SET and LINK_QUAL_PATTERN_SET [1]: DP 2.0 E11 - 3.6.11.1 LTTPR DPTX_PHY Electrical Compliance [2]: Configuring UnigrafDPTC Controller - Automation Test Sequence https://www.keysight.com/us/en/assets/9922-01244/help-files/ D9040DPPC-DisplayPort-Test-Software-Online-Help-latest.chm Cc: Imre Deak <imre.deak@intel.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Or Cochvi <or.cochvi@intel.com> Signed-off-by: Khaled Almahallawy <khaled.almahallawy@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220916054900.415804-1-khaled.almahallawy@intel.com
2022-09-24drm: POC drm on dyndbg - use in core, 2 helpers, 3 drivers.Jim Cromie1-0/+13
Use DECLARE_DYNDBG_CLASSMAP across DRM: - in .c files, since macro defines/initializes a record - in drivers, $mod_{drv,drm,param}.c ie where param setup is done, since a classmap is param related - in drm/drm_print.c since existing __drm_debug param is defined there, and we ifdef it, and provide an elaborated alternative. - in drm_*_helper modules: dp/drm_dp - 1st item in makefile target drivers/gpu/drm/drm_crtc_helper.c - random pick iirc. Since these modules all use identical CLASSMAP declarations (ie: names and .class_id's) they will all respond together to "class DRM_UT_*" query-commands: :#> echo class DRM_UT_KMS +p > /proc/dynamic_debug/control NOTES: This changes __drm_debug from int to ulong, so BIT() is usable on it. DRM's enum drm_debug_category values need to sync with the index of their respective class-names here. Then .class_id == category, and dyndbg's class FOO mechanisms will enable drm_dbg(DRM_UT_KMS, ...). Though DRM needs consistent categories across all modules, thats not generally needed; modules X and Y could define FOO differently (ie a different NAME => class_id mapping), changes are made according to each module's private class-map. No callsites are actually selected by this patch, since none are class'd yet. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> Link: https://lore.kernel.org/r/20220912052852.1123868-3-jim.cromie@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-14Merge drm/drm-next into drm-misc-nextMaxime Ripard1-1/+3
We need 6.0-rc1 to merge the backlight rework PR. Signed-off-by: Maxime Ripard <maxime@cerno.tech>
2022-09-13drm/scdc: Document hotplug gotchasMaxime Ripard1-0/+13
There's some interactions between the SCDC setup and the disconnection / reconnection of displays. Let's document it and a solution. Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Maxime Ripard <maxime@cerno.tech> Link: https://lore.kernel.org/r/20220829134731.213478-9-maxime@cerno.tech
2022-09-12Merge tag 'amd-drm-next-6.1-2022-09-08' of ↵Dave Airlie1-1/+3
https://gitlab.freedesktop.org/agd5f/linux into drm-next amd-drm-next-6.1-2022-09-08: amdgpu: - Mode2 reset for RDNA2 - Lots of new DC documentation - Add documentation about different asic families - DSC improvements - Aldebaran fixes - Misc spelling and grammar fixes - GFXOFF stats support for vangogh - DC frame size fixes - NBIO 7.7 updates - DCN 3.2 updates - DCN 3.1.4 Updates - SMU 13.x updates - Misc bug fixes - Rework DC register offset handling - GC 11.x updates - PSP 13.x updates - SDMA 6.x updates - GMC 11.x updates - SR-IOV updates - PSP fixes for TA unloading - DSC passthrough support - Misc code cleanups amdkfd: - ISA fixes for some GC 10.3 IPs - Misc code cleanups radeon: - Delayed work flush fix - Use time_after for some jiffies calculations drm: - DSC passthrough aux support Signed-off-by: Dave Airlie <airlied@redhat.com> From: Alex Deucher <alexander.deucher@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220908155202.57862-1-alexander.deucher@amd.com
2022-09-08drm/dp_mst: Avoid deleting payloads for connectors staying enabledImre Deak1-0/+3
When an MST connector stays enabled during a commit the connector's MST state needs to be added to the atomic state, but the corresponding MST payload allocation shouldn't be set for deletion; fix such modesets by ensuring the above even if the connector was already enabled before the modeset. The issue led to the following: [ 761.992923] i915 0000:00:02.0: drm_WARN_ON(payload->delete) [ 761.992949] WARNING: CPU: 6 PID: 1401 at drivers/gpu/drm/display/drm_dp_mst_topology.c:4221 drm_dp_atomic_find_time_slots+0x236/0x280 [drm_display_helper] [ 761.992955] Modules linked in: snd_hda_intel i915 drm_buddy drm_display_helper drm_kms_helper ttm drm snd_hda_codec_hdmi snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core snd_pcm prime_numbers i2c_algo_bit syscopyarea sysfillrect sysimgblt fb_sys_fops x86_pkg_temp_thermal cdc_ether coretemp crct10dif_pclmul usbnet crc32_pclmul mii ghash_clmulni_intel e1000e mei_me ptp i2c_i801 pps_core mei i2c_smbus intel_lpss_pci fuse [last unloaded: drm] [ 761.992986] CPU: 6 PID: 1401 Comm: testdisplay Tainted: G U 6.0.0-rc4-imre+ #565 [ 761.992989] Hardware name: Intel Corporation Alder Lake Client Platform/AlderLake-P DDR5 RVP, BIOS ADLPFWI1.R00.3135.A00.2203251419 03/25/2022 [ 761.992990] RIP: 0010:drm_dp_atomic_find_time_slots+0x236/0x280 [drm_display_helper] [ 761.992994] Code: 4c 8b 67 50 4d 85 e4 75 03 4c 8b 27 e8 03 28 4e e1 48 c7 c1 8b 26 2c a0 4c 89 e2 48 c7 c7 a8 26 2c a0 48 89 c6 e8 31 d5 88 e1 <0f> 0b 49 8b 85 d0 00 00 00 4c 89 fa 48 c7 c6 a0 41 2c a0 48 8b 78 [ 761.992995] RSP: 0018:ffffc9000177ba60 EFLAGS: 00010286 [ 761.992998] RAX: 0000000000000000 RBX: ffff88810d2f1540 RCX: 0000000000000000 [ 761.992999] RDX: 0000000000000001 RSI: ffffffff82368a25 RDI: 00000000ffffffff [ 761.993000] RBP: ffff888142299d80 R08: ffff8884adbfdfe8 R09: 00000000ffefffff [ 761.993001] R10: ffff8884a6bfe000 R11: ffff8884ac443c30 R12: ffff888102972f90 [ 761.993002] R13: ffff8881163e2cf0 R14: 00000000000003ac R15: ffff88810c501000 [ 761.993003] FS: 00007f81e4c459c0(0000) GS:ffff888496500000(0000) knlGS:0000000000000000 [ 761.993004] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 761.993005] CR2: 0000555dac962a98 CR3: 0000000123a34006 CR4: 0000000000770ee0 [ 761.993006] PKRU: 55555554 [ 761.993007] Call Trace: [ 761.993009] <TASK> [ 761.993012] intel_dp_mst_compute_config+0x19a/0x350 [i915] [ 761.993090] intel_atomic_check+0xf37/0x3180 [i915] [ 761.993168] drm_atomic_check_only+0x5d3/0xa60 [drm] [ 761.993182] drm_atomic_commit+0x56/0xc0 [drm] [ 761.993192] ? drm_plane_get_damage_clips.cold+0x1c/0x1c [drm] [ 761.993204] drm_atomic_helper_set_config+0x78/0xc0 [drm_kms_helper] [ 761.993214] drm_mode_setcrtc+0x1ed/0x750 [drm] [ 761.993232] ? drm_mode_getcrtc+0x180/0x180 [drm] [ 761.993241] drm_ioctl_kernel+0xb5/0x150 [drm] [ 761.993252] drm_ioctl+0x203/0x3d0 [drm] [ 761.993261] ? drm_mode_getcrtc+0x180/0x180 [drm] [ 761.993276] __x64_sys_ioctl+0x8a/0xb0 [ 761.993281] do_syscall_64+0x38/0x90 [ 761.993285] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 761.993287] RIP: 0033:0x7f81e551aaff [ 761.993288] Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <41> 89 c0 3d 00 f0 ff ff 77 1f 48 8b 44 24 18 64 48 2b 04 25 28 00 [ 761.993290] RSP: 002b:00007fff4304af10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 [ 761.993292] RAX: ffffffffffffffda RBX: 00007fff4304afa0 RCX: 00007f81e551aaff [ 761.993293] RDX: 00007fff4304afa0 RSI: 00000000c06864a2 RDI: 0000000000000004 [ 761.993294] RBP: 00000000c06864a2 R08: 0000000000000000 R09: 0000555dac8a9c68 [ 761.993294] R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000008c4 [ 761.993295] R13: 0000000000000004 R14: 0000555dac8a9c68 R15: 00007fff4304b098 [ 761.993301] </TASK> Fixes: 083351e96386 ("drm/display/dp_mst: Fix modeset tracking in drm_dp_atomic_release_vcpi_slots()") Testcase: igt@testdisplay Cc: Lyude Paul <lyude@redhat.com> Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Lyude Paul <lyude@redhat.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220907142542.1681994-1-imre.deak@intel.com
2022-08-30drm/dp: add drm_dp_phy_name() for getting DP PHY nameJani Nikula1-0/+32
Add a helper for getting the DP PHY name. In the interest of caller simplicity and to avoid allocations and passing in of buffers, duplicate the const strings to return. It's a minor penalty to pay for simplicity in all the call sites. v2: Rebase, add kernel-doc, ensure non-NULL always Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/b08dc12a7e621a48ec35546d6cd1ed4b1434810d.1660553850.git.jani.nikula@intel.com
2022-08-23drm/display/dp_mst: Move all payload info into the atomic stateLyude Paul1-498/+226
Now that we've finally gotten rid of the non-atomic MST users leftover in the kernel, we can finally get rid of all of the legacy payload code we have and move as much as possible into the MST atomic state structs. The main purpose of this is to make the MST code a lot less confusing to work on, as there's a lot of duplicated logic that doesn't really need to be here. As well, this should make introducing features like fallback link retraining and DSC support far easier. Since the old payload code was pretty gnarly and there's a Lot of changes here, I expect this might be a bit difficult to review. So to make things as easy as possible for reviewers, I'll sum up how both the old and new code worked here (it took me a while to figure this out too!). The old MST code basically worked by maintaining two different payload tables - proposed_vcpis, and payloads. proposed_vcpis would hold the modified payload we wanted to push to the topology, while payloads held the payload table that was currently programmed in hardware. Modifications to proposed_vcpis would be handled through drm_dp_allocate_vcpi(), drm_dp_mst_deallocate_vcpi(), and drm_dp_mst_reset_vcpi_slots(). Then, they would be pushed via drm_dp_mst_update_payload_step1() and drm_dp_mst_update_payload_step2(). Furthermore, it's important to note how adding and removing VC payloads actually worked with drm_dp_mst_update_payload_step1(). When a VC payload is removed from the VC table, all VC payloads which come after the removed VC payload's slots must have their time slots shifted towards the start of the table. The old code handles this by looping through the entire payload table and recomputing the start slot for every payload in the topology from scratch. While very much overkill, this ends up doing the right thing because we always order the VCPIs for payloads from first to last starting timeslot. It's important to also note that drm_dp_mst_update_payload_step2() isn't actually limited to updating a single payload - the driver can use it to queue up multiple payload changes so that as many of them can be sent as possible before waiting for the ACT. This is -technically- not against spec, but as Wayne Lin has pointed out it's not consistently implemented correctly in hubs - so it might as well be. drm_dp_mst_update_payload_step2() is pretty self explanatory and basically the same between the old and new code, save for the fact we don't have a second step for deleting payloads anymore -and thus rename it to drm_dp_mst_add_payload_step2(). The new payload code stores all of the current payload info within the MST atomic state and computes as much of the state as possible ahead of time. This has the one exception of the starting timeslots for payloads, which can't be determined at atomic check time since the starting time slots will vary depending on what order CRTCs are enabled in the atomic state - which varies from driver to driver. These are still stored in the atomic MST state, but are only copied from the old MST state during atomic commit time. Likewise, this is when new start slots are determined. Adding/removing payloads now works much more closely to how things are described in the spec. When we delete a payload, we loop through the current list of payloads and update the start slots for any payloads whose time slots came after the payload we just deleted. Determining the starting time slots for new payloads being added is done by simply keeping track of where the end of the VC table is in drm_dp_mst_topology_mgr->next_start_slot. Additionally, it's worth noting that we no longer have a single update_payload() function. Instead, we now have drm_dp_mst_add_payload_step1|2() and drm_dp_mst_remove_payload(). As such, it's now left it up to the driver to figure out when to add or remove payloads. The driver already knows when it's disabling/enabling CRTCs, so it also already knows when payloads should be added or removed. Changes since v1: * Refactor around all of the completely dead code changes that are happening in amdgpu for some reason when they really shouldn't even be there in the first place… :\ * Remove mention of sending one ACT per series of payload updates. As Wayne Lin pointed out, there are apparently hubs on the market that don't work correctly with this scheme and require a separate ACT per payload update. * Fix accidental drop of mst_mgr.lock - Wayne Lin * Remove mentions of allowing multiple ACT updates per payload change, mention that this is a result of vendors not consistently supporting this part of the spec and requiring a unique ACT for each payload change. * Get rid of reference to drm_dp_mst_port in DC - turns out I just got myself confused by DC and we don't actually need this. Changes since v2: * Get rid of fix for not sending payload deallocations if ddps=0 and just go back to wayne's fix Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-18-lyude@redhat.com
2022-08-23drm/display/dp_mst: Maintain time slot allocations when deleting payloadsLyude Paul1-7/+7
Currently, we set drm_dp_atomic_payload->time_slots to 0 in order to indicate that we're about to delete a payload in the current atomic state. Since we're going to be dropping all of the legacy code for handling the payload table however, we need to be able to ensure that we still keep track of the current time slot allocations for each payload so we can reuse this info when asking the root MST hub to delete payloads. We'll also be using it to recalculate the start slots of each VC. So, let's keep track of the intent of a payload in drm_dp_atomic_payload by adding ->delete, which we set whenever we're planning on deleting a payload during the current atomic commit. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-16-lyude@redhat.com
2022-08-23drm/display/dp_mst: Drop all ports from topology on CSNs before queueing ↵Lyude Paul1-6/+8
link address work We want to start cutting down on all of the places that we use port validation, so that ports may be removed from the topology as quickly as possible to minimize the number of errors we run into as a result of being out of sync with the current topology status. This isn't a very typical scenario and I don't think I've ever even run into it - but since the next commit is going to make some changes to payload updates depending on their hotplug status I think it's a probably good idea to take precautions. Let's do this with CSNs by moving some code around so that we only queue link address probing work at the end of handling all CSNs - allowing us to make sure we drop as many topology references as we can beforehand. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-15-lyude@redhat.com
2022-08-23drm/display/dp_mst: Add helpers for serializing SST <-> MST transitionsLyude Paul1-0/+59
There's another kind of situation where we could potentially race with nonblocking modesets and MST, especially if we were to only use the locking provided by atomic modesetting: * Display 1 begins as enabled on DP-1 in SST mode * Display 1 switches to MST mode, exposes one sink in MST mode * Userspace does non-blocking modeset to disable the SST display * Userspace does non-blocking modeset to enable the MST display with a different CRTC, but the SST display hasn't been fully taken down yet * Execution order between the last two commits isn't guaranteed since they share no drm resources We can fix this however, by ensuring that we always pull in the atomic topology state whenever a connector capable of driving an MST display performs its atomic check - and then tracking CRTC commits happening on the SST connector in the MST topology state. So, let's add some simple helpers for doing that and hook them up in various drivers. v2: * Use intel_dp_mst_source_support() to check for MST support in i915, fixes CI failures Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-14-lyude@redhat.com
2022-08-23drm/display/dp_mst: Fix modeset tracking in drm_dp_atomic_release_vcpi_slots()Lyude Paul1-3/+8
Currently with the MST helpers we avoid releasing payloads _and_ avoid pulling in the MST state if there aren't any actual payload changes. While we want to keep the first step, we need to now make sure that we're always pulling in the MST state on all modesets that can modify payloads - even if the resulting payloads in the atomic state are identical to the previous ones. This is mainly to make it so that if a CRTC is still assigned to a connector but is set to DPMS off, the CRTC still holds it's payload allocation in the atomic state and still appropriately pulls in the MST state for commit tracking. Otherwise, we'll occasionally forget to update MST payloads from changes caused by non-atomic DPMS changes. Doing this also allows us to track bandwidth limitations in a state correctly even between DPMS changes, so that there's no chance of a simple ->active change being rejected by the atomic check. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-11-lyude@redhat.com
2022-08-23drm/display/dp_mst: Don't open code modeset checks for releasing time slotsLyude Paul1-3/+18
I'm not sure why, but at the time I originally wrote the find/release time slot helpers I thought we should avoid keeping modeset tracking out of the MST helpers. In retrospect though there's no actual good reason to do this, and the logic has ended up being identical across all the drivers using the helpers. Also, it needs to be fixed anyway so we don't break things when going atomic-only with MST. So, let's just move this code into drm_dp_atomic_release_time_slots() and stop open coding it. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-10-lyude@redhat.com
2022-08-23drm/display/dp_mst: Add nonblocking helpers for DP MSTLyude Paul1-0/+93
As Daniel Vetter pointed out, if we only use the atomic modesetting locks with MST it's technically possible for a driver with non-blocking modesets to race when it comes to MST displays - as we make the mistake of not doing our own CRTC commit tracking in the topology_state object. This could potentially cause problems if something like this happens: * User starts non-blocking commit to disable CRTC-1 on MST topology 1 * User starts non-blocking commit to enable CRTC-2 on MST topology 1 There's no guarantee here that the commit for disabling CRTC-2 will only occur after CRTC-1 has finished, since neither commit shares a CRTC - only the private modesetting object for MST. Keep in mind this likely isn't a problem for blocking modesets, only non-blocking. So, begin fixing this by keeping track of which CRTCs on a topology have changed by keeping track of which CRTCs we release or allocate timeslots on. As well, add some helpers for: * Setting up the drm_crtc_commit structs in the ->commit_setup hook * Waiting for any CRTC dependencies from the previous topology state v2: * Use drm_dp_mst_atomic_setup_commit() directly - Jani Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-9-lyude@redhat.com
2022-08-23drm/display/dp_mst: Add helper for finding payloads in atomic MST stateLyude Paul1-64/+45
We already open-code this quite often, and will be iterating through payloads even more once we've moved all of the payload tracking into the atomic state. So, let's add a helper for doing this. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-8-lyude@redhat.com
2022-08-23drm/display/dp_mst: Fix confusing docs for drm_dp_atomic_release_time_slots()Lyude Paul1-2/+1
For some reason we mention returning 0 if "slots have been added back to drm_dp_mst_topology_state->avail_slots". This is totally misleading, avail_slots is simply for figuring out the total number of slots available in total on the topology and has no relation to the current payload allocations. So, let's get rid of that comment. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-6-lyude@redhat.com
2022-08-23drm/display/dp_mst: Call them time slots, not VCPI slotsLyude Paul1-53/+53
VCPI is only sort of the correct term here, originally the majority of this code simply referred to timeslots vaguely as "slots" - and since I started working on it and adding atomic functionality, the name "VCPI slots" has been used to represent time slots. Now that we actually have consistent access to the DisplayPort spec thanks to VESA, I now know this isn't actually the proper term - as the specification refers to these as time slots. Since we're trying to make this code as easy to figure out as possible, let's take this opportunity to correct this nomenclature and call them by their proper name - timeslots. Likewise, we rename various functions appropriately, along with replacing references in the kernel documentation and various debugging messages. It's important to note that this patch series leaves the legacy MST code untouched for the most part, which is fine since we'll be removing it soon anyhow. There should be no functional changes in this series. v2: * Add note that Wayne Lin from AMD suggested regarding slots being between the source DP Tx and the immediate downstream DP Rx Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-5-lyude@redhat.com
2022-08-23drm/display/dp_mst: Rename drm_dp_mst_vcpi_allocationLyude Paul1-48/+48
In retrospect, the name I chose for this originally is confusing, as there's a lot more info in here then just the VCPI. This really should be called a payload. Let's make it more obvious that this is meant to be related to the atomic state and is about payloads by renaming it to drm_dp_mst_atomic_payload. Also, rename various variables throughout the code that use atomic payloads. Signed-off-by: Lyude Paul <lyude@redhat.com> Cc: Wayne Lin <Wayne.Lin@amd.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Fangzhi Zuo <Jerry.Zuo@amd.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Imre Deak <imre.deak@intel.com> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Sean Paul <sean@poorly.run> Acked-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220817193847.557945-4-lyude@redhat.com
2022-08-17drm/dp_mst: add passthrough_aux to struct drm_dp_mst_portHamza Mahfooz1-1/+3
Currently, there is no way to identify if DSC pass-through can be enabled and what aux DSC pass-through requests ought to be sent to. So, add a variable to struct drm_dp_mst_port that keeps track of the aforementioned information. Reviewed-by: Lyude Paul <lyude@redhat.com> Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
2022-07-29drm/dp_mst: fix drm_dp_dpcd_read return value checksSimon Ser1-3/+3
drm_dp_dpcd_read returns the number of bytes read. The previous code would print garbage on DPCD error, and would exit with on error on success. Signed-off-by: Simon Ser <contact@emersion.fr> Fixes: cb897542c6d2 ("drm/dp_mst: Fix W=1 warnings") Cc: Lyude Paul <lyude@redhat.com> Cc: Benjamin Gaignard <benjamin.gaignard@st.com> Reviewed-by: Jani Nikula <jani.nikula@intel.com> Link: https://patchwork.freedesktop.org/patch/473500/
2022-07-19drm:delete the repeated word "the" in commentsshaomin Deng1-1/+1
remove the rebundant word "the" from comments. Signed-off-by: shaomin Deng <dengshaomin@cdjrlc.com> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Link: https://patchwork.freedesktop.org/patch/msgid/20220718151154.9628-1-dengshaomin@cdjrlc.com
2022-07-05drm: Remove linux/fb.h from drm_crtc.hVille Syrjälä1-0/+1
drm_crtc.h has no need for linux/fb.h, so don't include it. Avoids useless rebuilds of the entire universe when touching linux/fb.h. Quite a few placs do currently depend on linux/fb.h or other headers pulled in by it without actually including any of it directly. All of those need to be fixed up. v2: Split the vmwgfx change out Acked-by: Sam Ravnborg <sam@ravnborg.org> Acked-by: Jani Nikula <jani.nikula@intel.com> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220630195114.17407-3-ville.syrjala@linux.intel.com
2022-06-23drm/display: Fix build error without CONFIG_OFYueHaibing1-1/+1
While CONFIG_OF is n but COMPILE_TEST is y, we got this: WARNING: unmet direct dependencies detected for DRM_DP_AUX_BUS Depends on [n]: HAS_IOMEM [=y] && DRM [=y] && OF [=n] Selected by [y]: - DRM_MSM [=y] && HAS_IOMEM [=y] && DRM [=y] && (ARCH_QCOM || SOC_IMX5 || COMPILE_TEST [=y]) && COMMON_CLK [=y] && IOMMU_SUPPORT [=y] && (QCOM_OCMEM [=n] || QCOM_OCMEM [=n]=n) && (QCOM_LLCC [=y] || QCOM_LLCC [=y]=n) && (QCOM_COMMAND_DB [=n] || QCOM_COMMAND_DB [=n]=n) Make DRM_DP_AUX_BUS depends on OF || COMPILE_TEST to fix this warning. Fixes: 1e0f66420b13 ("drm/display: Introduce a DRM display-helper module") Signed-off-by: YueHaibing <yuehaibing@huawei.com> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org> Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Link: https://patchwork.freedesktop.org/patch/msgid/20220611041612.1976-1-yuehaibing@huawei.com
2022-06-21drm/dp_mst: Get rid of old comment in drm_atomic_get_mst_topology_state docsLyude Paul1-2/+1
We don't actually care about connection_mutex here anymore, so let's get rid of the comment mentioning it in this function's kdocs. Signed-off-by: Lyude Paul <lyude@redhat.com> Reviewed-by: Wayne Lin <Wayne.Lin@amd.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220602201757.30431-4-lyude@redhat.com