kernel/linux.git/drivers/gpu/drm/display, branch v6.12.80

drm/display/dp_mst: Add protection against 0 vcpi

2026-03-04T12:20:59+00:00

[ Upstream commit 342ccffd9f77fc29fe1c05fd145e4d842bd2feaa ] When releasing a timeslot there is a slight chance we may end up with the wrong payload mask due to overflow if the delayed_destroy_work ends up coming into play after a DP 2.1 monitor gets disconnected which causes vcpi to become 0 then we try to make the payload = ~BIT(vcpi - 1) which is a negative shift. VCPI id should never really be 0 hence skip changing the payload mask if VCPI is 0. Otherwise it leads to <7> [515.287237] xe 0000:03:00.0: [drm:drm_dp_mst_get_port_malloc [drm_display_helper]] port ffff888126ce9000 (3) <4> [515.287267] -----------[ cut here ]----------- <3> [515.287268] UBSAN: shift-out-of-bounds in ../drivers/gpu/drm/display/drm_dp_mst_topology.c:4575:36 <3> [515.287271] shift exponent -1 is negative <4> [515.287275] CPU: 7 UID: 0 PID: 3108 Comm: kworker/u64:33 Tainted: G S U 6.17.0-rc6-lgci-xe-xe-3795-3e79699fa1b216e92+ #1 PREEMPT(voluntary) <4> [515.287279] Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER <4> [515.287279] Hardware name: ASUS System Product Name/PRIME Z790-P WIFI, BIOS 1645 03/15/2024 <4> [515.287281] Workqueue: drm_dp_mst_wq drm_dp_delayed_destroy_work [drm_display_helper] <4> [515.287303] Call Trace: <4> [515.287304] <4> [515.287306] dump_stack_lvl+0xc1/0xf0 <4> [515.287313] dump_stack+0x10/0x20 <4> [515.287316] __ubsan_handle_shift_out_of_bounds+0x133/0x2e0 <4> [515.287324] ? drm_atomic_get_private_obj_state+0x186/0x1d0 <4> [515.287333] drm_dp_atomic_release_time_slots.cold+0x17/0x3d [drm_display_helper] <4> [515.287355] mst_connector_atomic_check+0x159/0x180 [xe] <4> [515.287546] drm_atomic_helper_check_modeset+0x4d9/0xfa0 <4> [515.287550] ? __ww_mutex_lock.constprop.0+0x6f/0x1a60 <4> [515.287562] intel_atomic_check+0x119/0x2b80 [xe] <4> [515.287740] ? find_held_lock+0x31/0x90 <4> [515.287747] ? lock_release+0xce/0x2a0 <4> [515.287754] drm_atomic_check_only+0x6a2/0xb40 <4> [515.287758] ? drm_atomic_add_affected_connectors+0x12b/0x140 <4> [515.287765] drm_atomic_commit+0x6e/0xf0 <4> [515.287766] ? _pfx__drm_printfn_info+0x10/0x10 <4> [515.287774] drm_client_modeset_commit_atomic+0x25c/0x2b0 <4> [515.287794] drm_client_modeset_commit_locked+0x60/0x1b0 <4> [515.287795] ? mutex_lock_nested+0x1b/0x30 <4> [515.287801] drm_client_modeset_commit+0x26/0x50 <4> [515.287804] __drm_fb_helper_restore_fbdev_mode_unlocked+0xdc/0x110 <4> [515.287810] drm_fb_helper_hotplug_event+0x120/0x140 <4> [515.287814] drm_fbdev_client_hotplug+0x28/0xd0 <4> [515.287819] drm_client_hotplug+0x6c/0xf0 <4> [515.287824] drm_client_dev_hotplug+0x9e/0xd0 <4> [515.287829] drm_kms_helper_hotplug_event+0x1a/0x30 <4> [515.287834] drm_dp_delayed_destroy_work+0x3df/0x410 [drm_display_helper] <4> [515.287861] process_one_work+0x22b/0x6f0 <4> [515.287874] worker_thread+0x1e8/0x3d0 <4> [515.287879] ? __pfx_worker_thread+0x10/0x10 <4> [515.287882] kthread+0x11c/0x250 <4> [515.287886] ? __pfx_kthread+0x10/0x10 <4> [515.287890] ret_from_fork+0x2d7/0x310 <4> [515.287894] ? __pfx_kthread+0x10/0x10 <4> [515.287897] ret_from_fork_asm+0x1a/0x30 Closes: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/6303 Signed-off-by: Suraj Kandpal Reviewed-by: Imre Deak Reviewed-by: Lyude Paul Link: https://patch.msgid.link/20251119094650.799135-1-suraj.kandpal@intel.com Signed-off-by: Sasha Levin

Revert "drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS"

2025-09-04T13:31:56+00:00

This reverts commit 3c778a98bee16b4c7ba364a0101ee3c399a95b85 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 Link: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14558 Signed-off-by: Imre Deak Signed-off-by: Greg Kroah-Hartman

drm/dp: Change AUX DPCD probe address from DPCD_REV to LANE0_1_STATUS

2025-08-28T14:31:08+00:00

[ 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: Cc: Ville Syrjälä Cc: Jani Nikula Acked-by: Jani Nikula Signed-off-by: Imre Deak Link: https://lore.kernel.org/r/20250605082850.65136-2-imre.deak@intel.com Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

drm/dp_mst: Fix drm RAD print

2025-04-10T12:39:13+00:00

[ 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 Cc: Ville Syrjälä Cc: Harry Wentland Cc: Lyude Paul Reviewed-by: Lyude Paul Signed-off-by: Wayne Lin Signed-off-by: Lyude Paul Link: https://patchwork.freedesktop.org/patch/msgid/20250113091100.3314533-2-Wayne.Lin@amd.com Signed-off-by: Sasha Levin

drm/dp_mst: Fix locking when skipping CSN before topology probing

2025-03-22T19:54:23+00:00

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 Cc: Lyude Paul Cc: stable@vger.kernel.org # v6.6+ Reviewed-by: Wayne Lin Reviewed-by: Lyude Paul Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/20250307183152.3822170-1-imre.deak@intel.com Signed-off-by: Greg Kroah-Hartman

drm: Fix DSC BPP increment decoding

2025-02-21T13:01:21+00:00

[ Upstream commit e00a2e5d485faf53c7a24b9d1b575a642227947f ] Starting with DPCD version 2.0 bits 6:3 of the DP_DSC_BITS_PER_PIXEL_INC DPCD register contains the NativeYCbCr422_MAX_bpp_DELTA field, which can be non-zero as opposed to earlier DPCD versions, hence decoding the bit_per_pixel increment value at bits 2:0 in the same register requires applying a mask, do so. Cc: Ankit Nautiyal Fixes: 0c2287c96521 ("drm/display/dp: Add helper function to get DSC bpp precision") Reviewed-by: Jani Nikula Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/20250212161851.4007005-1-imre.deak@intel.com Signed-off-by: Sasha Levin

gpu: drm_dp_cec: fix broken CEC adapter properties check

2025-02-17T09:04:58+00:00

[ 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 Reported-by: Farblos Reviewed-by: Dmitry Baryshkov Fixes: 2c6d1fffa1d9 ("drm: add support for DisplayPort CEC-Tunneling-over-AUX") Tested-by: Farblos Link: https://patchwork.freedesktop.org/patch/msgid/361bb03d-1691-4e23-84da-0861ead5dbdc@xs4all.nl Signed-off-by: Dmitry Baryshkov Signed-off-by: Sasha Levin

drm/connector: Allow clearing HDMI infoframes

2025-02-08T08:56:57+00:00

[ Upstream commit d34357743b360c99903b5a59daab08f55b2f41a1 ] Our infoframe setting code currently lacks the ability to clear infoframes. For some of the infoframes, we only need to replace them, so if an error occurred when generating a new infoframe we would leave a stale frame instead of clearing the frame. However, the Dynamic Range and Mastering (DRM) infoframe should only be present when displaying HDR content (ie: the HDR_OUTPUT_METADATA blob is set). If we can't clear infoframes, the stale DRM infoframe will remain and we can never set the display back to SDR mode. With this change, we clear infoframes when they can not, or should not, be generated. This fixes switching to an SDR mode from an HDR one. Fixes: f378b77227bc ("drm/connector: hdmi: Add Infoframes generation") Signed-off-by: Derek Foreman Reviewed-by: AngeloGioacchino Del Regno Reviewed-by: Dmitry Baryshkov Link: https://patchwork.freedesktop.org/patch/msgid/20241202181939.724011-1-derek.foreman@collabora.com Signed-off-by: Maxime Ripard Signed-off-by: Sasha Levin

drm/dp_mst: Ensure mst_primary pointer is valid in drm_dp_mst_handle_up_req()

2025-01-02T09:34:20+00:00

[ 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 Reviewed-by: Lyude Paul (v1) Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/20241204132007.3132494-1-imre.deak@intel.com Signed-off-by: Sasha Levin

drm/display: use ERR_PTR on DP tunnel manager creation fail

2024-12-27T13:02:09+00:00

commit 080b2e7b5e9ad23343e4b11f0751e4c724a78958 upstream. Instead of returning a generic NULL on error from drm_dp_tunnel_mgr_create(), use error pointers with informative codes to align the function with stub that is executed when CONFIG_DRM_DISPLAY_DP_TUNNEL is unset. This will also trigger IS_ERR() in current caller (intel_dp_tunnerl_mgr_init()) instead of bypassing it via NULL pointer. v2: use error codes inside drm_dp_tunnel_mgr_create() instead of handling on caller's side (Michal, Imre) v3: fixup commit message and add "CC"/"Fixes" lines (Andi), mention aligning function code with stub Fixes: 91888b5b1ad2 ("drm/i915/dp: Add support for DP tunnel BW allocation") Cc: Imre Deak Cc: # v6.9+ Signed-off-by: Krzysztof Karas Reviewed-by: Andi Shyti Signed-off-by: Imre Deak Link: https://patchwork.freedesktop.org/patch/msgid/7q4fpnmmztmchczjewgm6igy55qt6jsm7tfd4fl4ucfq6yg2oy@q4lxtsu6445c Signed-off-by: Greg Kroah-Hartman