kernel/linux.git/drivers/gpu/drm/drm_vblank.c, branch v6.6.150

drm/vblank: Fix for drivers that do not drm_vblank_init()

2023-04-04T20:38:03+00:00

This should fix a crash that was reported on ast (and possibly other drivers which do not initialize vblank). fbcon: Taking over console Unable to handle kernel NULL pointer dereference at virtual address 0000000000000074 Mem abort info: ESR = 0x0000000096000004 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x04: level 0 translation fault Data abort info: ISV = 0, ISS = 0x00000004 CM = 0, WnR = 0 user pgtable: 4k pages, 48-bit VAs, pgdp=0000080009d16000 [0000000000000074] pgd=0000000000000000, p4d=0000000000000000 Internal error: Oops: 0000000096000004 [#1] SMP Modules linked in: ip6table_nat tun nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 rfkill ip_set nf_tables nfnetlink qrtr sunrpc binfmt_misc vfat fat xfs snd_usb_audio snd_hwdep snd_usbmidi_lib snd_seq snd_pcm snd_rawmidi snd_timer snd_seq_device snd soundcore joydev mc ipmi_ssif ipmi_devintf ipmi_msghandler arm_spe_pmu arm_cmn arm_dsu_pmu arm_dmc620_pmu cppc_cpufreq loop zram crct10dif_ce polyval_ce nvme polyval_generic ghash_ce sbsa_gwdt igb nvme_core ast nvme_common i2c_algo_bit xgene_hwmon gpio_dwapb scsi_dh_rdac scsi_dh_emc scsi_dh_alua ip6_tables ip_tables dm_multipath fuse CPU: 12 PID: 469 Comm: kworker/12:1 Not tainted 6.3.0-rc2-00008-gd39e48ca80c0 #1 Hardware name: ADLINK AVA Developer Platform/AVA Developer Platform, BIOS TianoCore 2.04.100.07 (SYS: 2.06.20220308) 09/08/2022 Workqueue: events fbcon_register_existing_fbs pstate: 20400009 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : drm_crtc_next_vblank_start+0x2c/0x98 lr : drm_atomic_helper_wait_for_fences+0x90/0x240 sp : ffff80000d583960 x29: ffff80000d583960 x28: ffff07ff8fc187b0 x27: 0000000000000000 x26: ffff07ff99c08c00 x25: 0000000000000038 x24: ffff07ff99c0c000 x23: 0000000000000001 x22: 0000000000000038 x21: 0000000000000000 x20: ffff07ff9640a280 x19: 0000000000000000 x18: ffffffffffffffff x17: 0000000000000000 x16: ffffb24d2eece1c0 x15: 0000003038303178 x14: 3032393100000048 x13: 0000000000000000 x12: 0000000000000000 x11: 0000000000000000 x10: 0000000000000000 x9 : ffffb24d2eeeaca0 x8 : ffff80000d583628 x7 : 0000080077783000 x6 : 0000000000000000 x5 : ffff80000d584000 x4 : ffff07ff99c0c000 x3 : 0000000000000130 x2 : 0000000000000000 x1 : ffff80000d5839c0 x0 : ffff07ff99c0cc08 Call trace: drm_crtc_next_vblank_start+0x2c/0x98 drm_atomic_helper_wait_for_fences+0x90/0x240 drm_atomic_helper_commit+0xb0/0x188 drm_atomic_commit+0xb0/0xf0 drm_client_modeset_commit_atomic+0x218/0x280 drm_client_modeset_commit_locked+0x64/0x1a0 drm_client_modeset_commit+0x38/0x68 __drm_fb_helper_restore_fbdev_mode_unlocked+0xb0/0xf8 drm_fb_helper_set_par+0x44/0x88 fbcon_init+0x1e0/0x4a8 visual_init+0xbc/0x118 do_bind_con_driver.isra.0+0x194/0x3a0 do_take_over_console+0x50/0x70 do_fbcon_takeover+0x74/0xf8 do_fb_registered+0x13c/0x158 fbcon_register_existing_fbs+0x78/0xc0 process_one_work+0x1ec/0x478 worker_thread+0x74/0x418 kthread+0xec/0x100 ret_from_fork+0x10/0x20 Code: f9400004 b9409013 f940a082 9ba30a73 (b9407662) ---[ end trace 0000000000000000 ]--- v2: Use drm_dev_has_vblank() Reported-by: Nathan Chancellor Fixes: d39e48ca80c0 ("drm/atomic-helper: Set fence deadline for vblank") Signed-off-by: Rob Clark Reviewed-by: Thomas Zimmermann Tested-by: Nathan Chancellor Tested-by: Geert Uytterhoeven Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20230403160314.1210533-1-robdclark@gmail.com

drm/vblank: Add helper to get next vblank time

2023-03-28T21:52:59+00:00

Will be used in the next commit to set a deadline on fences that an atomic update is waiting on. v2: Calculate time at *start* of vblank period, not end v3: Fix kbuild complaints Signed-off-by: Rob Clark Reviewed-by: Mario Kleiner

drm: Use drm_mode_copy()

2022-04-12T06:27:20+00:00

struct drm_display_mode embeds a list head, so overwriting the full struct with another one will corrupt the list (if the destination mode is on a list). Use drm_mode_copy() instead which explicitly preserves the list head of the destination mode. Even if we know the destination mode is not on any list using drm_mode_copy() seems decent as it sets a good example. Bad examples of not using it might eventually get copied into code where preserving the list head actually matters. Obviously one case not covered here is when the mode itself is embedded in a larger structure and the whole structure is copied. But if we are careful when copying into modes embedded in structures I think we can be a little more reassured that bogus list heads haven't been propagated in. @is_mode_copy@ @@ drm_mode_copy(...) { ... } @depends on !is_mode_copy@ struct drm_display_mode *mode; expression E, S; @@ ( - *mode = E + drm_mode_copy(mode, &E) | - memcpy(mode, E, S) + drm_mode_copy(mode, E) ) @depends on !is_mode_copy@ struct drm_display_mode mode; expression E; @@ ( - mode = E + drm_mode_copy(&mode, &E) | - memcpy(&mode, E, S) + drm_mode_copy(&mode, E) ) @@ struct drm_display_mode *mode; @@ - &*mode + mode Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20220218100403.7028-23-ville.syrjala@linux.intel.com Reviewed-by: Andrzej Hajda

drm: IRQ midlayer is now legacy

2021-08-10T18:14:01+00:00

Hide the DRM midlayer behind CONFIG_DRM_LEGACY, make functions use the prefix drm_legacy_, and move declarations to drm_legacy.h. In struct drm_device, move the fields irq and irq_enabled behind CONFIG_DRM_LEGACY. All callers have been updated. Signed-off-by: Thomas Zimmermann Acked-by: Sam Ravnborg Link: https://patchwork.freedesktop.org/patch/msgid/20210803090704.32152-15-tzimmermann@suse.de

drm: Fix typo in comments

2021-08-02T08:19:43+00:00

fix typo for drm v1->v2: respin with the change "iff ==> implies that" Signed-off-by: Cai Huoqing Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210730132729.376-1-caihuoqing@baidu.com

drm: Don't test for IRQ support in VBLANK ioctls

2021-06-29T09:03:39+00:00

For KMS drivers, replace the IRQ check in VBLANK ioctls with a check for vblank support. IRQs might be enabled wthout vblanking being supported. This change also removes the DRM framework's only dependency on IRQ state for non-legacy drivers. For legacy drivers with userspace modesetting, the original test remains in drm_wait_vblank_ioctl(). v4: * avoid preprocessor ifdef in drm_wait_vblank_ioctl() (Jani, Thierry) v3: * optimize test in drm_wait_vblank_ioctl() for KMS case (Liviu) * update docs for drm_irq_uninstall() v2: * keep the old test for legacy drivers in drm_wait_vblank_ioctl() (Daniel) Signed-off-by: Thomas Zimmermann Reviewed-by: Laurent Pinchart Reviewed-by: Liviu Dudau Acked-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210625082222.3845-5-tzimmermann@suse.de

drm/vblank: Do not store a new vblank timestamp in drm_vblank_restore()

2021-04-01T17:29:17+00:00

drm_vblank_restore() exists because certain power saving states can clobber the hardware frame counter. The way it does this is by guesstimating how many frames were missed purely based on the difference between the last stored timestamp vs. a newly sampled timestamp. If we should call this function before a full frame has elapsed since we sampled the last timestamp we would end up with a possibly slightly different timestamp value for the same frame. Currently we will happily overwrite the already stored timestamp for the frame with the new value. This could cause userspace to observe two different timestamps for the same frame (and the timestamp could even go backwards depending on how much error we introduce when correcting the timestamp based on the scanout position). To avoid that let's not update the stored timestamp at all, and instead we just fix up the last recorded hw vblank counter value such that the already stored timestamp/seq number will match. Thus the next time a vblank irq happens it will calculate the correct diff between the current and stored hw vblank counter values. Sidenote: Another possible idea that came to mind would be to do this correction only if the power really was removed since the last time we sampled the hw frame counter. But to do that we would need a robust way to detect when it has occurred. Some possibilities could involve some kind of hardare power well transition counter, or potentially we could store a magic value in a scratch register that lives in the same power well. But I'm not sure either of those exist, so would need an actual investigation to find out. All of that is very hardware specific of course, so would have to be done in the driver code. Cc: Dhinakaran Pandiyan Cc: Rodrigo Vivi Cc: Daniel Vetter Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20210218160305.16711-1-ville.syrjala@linux.intel.com Reviewed-by: Daniel Vetter

drm/vblank: Document drm_crtc_vblank_restore constraints

2021-02-10T11:38:55+00:00

I got real badly confused when trying to review a fix from Ville for this. Let's try to document better what's required for this, and check the minimal settings at runtime - we can't check ofc that there's indeed no races in the driver callback. Also noticed that the drm_vblank_restore version is unused, so lets unexport that while at it. Reviewed-by: Ville Syrjälä Cc: Ville Syrjala Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210209101523.2954281-1-daniel.vetter@ffwll.ch

drm/drm_vblank: set the dma-fence timestamp during send_vblank_event

2021-01-22T10:52:29+00:00

The explicit out-fences in crtc are signaled as part of vblank event, indicating all framebuffers present on the Atomic Commit request are scanned out on the screen. Though the fence signal and the vblank event notification happens at the same time, triggered by the same hardware vsync event, the timestamp set in both are different. With drivers supporting precise vblank timestamp the difference between the two timestamps would be even higher. This might have an impact on use-mode frameworks using these fence timestamps for purposes other than simple buffer usage. For instance, the Android framework [1] uses the retire-fences as an alternative to vblank when frame-updates are in progress. Set the fence timestamp during send vblank event using a new drm_send_event_timestamp_locked variant to avoid discrepancies. [1] https://android.googlesource.com/platform/frameworks/native/+/master/ services/surfaceflinger/Scheduler/Scheduler.cpp#397 Changes in v2: - Use drm_send_event_timestamp_locked to update fence timestamp - add more information to commit text Changes in v3: - use same backend helper function for variants of drm_send_event to avoid code duplications Changes in v4: - remove WARN_ON from drm_send_event_timestamp_locked Signed-off-by: Veera Sundaram Sankaran Reviewed-by: John Stultz Signed-off-by: Sumit Semwal [sumits: minor parenthesis alignment correction] Link: https://patchwork.freedesktop.org/patch/msgid/1610757107-11892-2-git-send-email-veeras@codeaurora.org

drm/vblank: Fix typo in docs

2021-01-14T14:47:45+00:00

Fix typo in intro chapter in drm_vblank.c. Change 'sacn' to 'scan'. Signed-off-by: Sumera Priyadarsini Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20210114142245.udr7v2aa43ho56xs@adolin