kernel/include/drm/drm_modeset_lock.h, branch linux-6.18.y

drm/locking: fix drm_modeset_acquire_ctx kernel-doc

2022-01-20T12:41:25Z

The stack_depot member was added without kernel-doc, leading to below warning. Fix it. ./include/drm/drm_modeset_lock.h:74: warning: Function parameter or member 'stack_depot' not described in 'drm_modeset_acquire_ctx' Reported-by: Stephen Rothwell Fixes: cd06ab2fd48f ("drm/locking: add backtrace for locking contended locks without backoff") Signed-off-by: Jani Nikula Reviewed-by: Daniel Vetter Tested-by: Stephen Rothwell Link: https://patchwork.freedesktop.org/patch/msgid/20220120094856.3004147-1-jani.nikula@intel.com

drm/locking: add backtrace for locking contended locks without backoff

2021-10-13T12:54:46Z

If drm_modeset_lock() returns -EDEADLK, the caller is supposed to drop all currently held locks using drm_modeset_backoff(). Failing to do so will result in warnings and backtraces on the paths trying to lock a contended lock. Add support for optionally printing the backtrace on the path that hit the deadlock and didn't gracefully handle the situation. For example, the patch [1] inadvertently dropped the return value check and error return on replacing calc_watermark_data() with intel_compute_global_watermarks(). The backtraces on the subsequent locking paths hitting WARN_ON(ctx->contended) were unhelpful, but adding the backtrace to the deadlock path produced this helpful printout: <7> [98.002465] drm_modeset_lock attempting to lock a contended lock without backoff: drm_modeset_lock+0x107/0x130 drm_atomic_get_plane_state+0x76/0x150 skl_compute_wm+0x251d/0x2b20 [i915] intel_atomic_check+0x1942/0x29e0 [i915] drm_atomic_check_only+0x554/0x910 drm_atomic_nonblocking_commit+0xe/0x50 drm_mode_atomic_ioctl+0x8c2/0xab0 drm_ioctl_kernel+0xac/0x140 Add new CONFIG_DRM_DEBUG_MODESET_LOCK to enable modeset lock debugging with stack depot and trace. [1] https://lore.kernel.org/r/20210924114741.15940-4-jani.nikula@intel.com v2: - default y if DEBUG_WW_MUTEX_SLOWPATH (Daniel) - depends on DEBUG_KERNEL Cc: Daniel Vetter Cc: Dave Airlie Reviewed-by: Daniel Vetter Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20211001091444.8177-1-jani.nikula@intel.com

Revert "drm: cleanup: remove drm_modeset_(un)lock_all()"

2021-10-04T13:34:55Z

This reverts commit 8d813d1a535c8c7503a5f4061654a73026be8c5e. This patchset breaks on intel platforms and was previously NACK'd by Ville. Cc: Ville Syrjälä Cc: Fernando Ramos Acked-by: Ville Syrjälä Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20211002154542.15800-1-sean@poorly.run

drm: cleanup: remove drm_modeset_(un)lock_all()

2021-10-01T17:01:01Z

Functions drm_modeset_lock_all() and drm_modeset_unlock_all() are no longer used anywhere and can be removed. Signed-off-by: Fernando Ramos Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20210924064324.229457-17-greenfoo@u92.eu

drm/modeset-lock: Take the modeset BKL for legacy drivers

2020-08-17T17:41:50Z

This fell off in the conversion in commit 9bcaa3fe58ab7559e71df798bcff6e0795158695 Author: Michal Orzel Date: Tue Apr 28 19:10:04 2020 +0200 drm: Replace drm_modeset_lock/unlock_all with DRM_MODESET_LOCK_ALL_* helpers but it's caught by the drm_warn_on_modeset_not_all_locked() that the legacy modeset code uses. Since this is the bkl and it's unclear what's all protected, play it safe and grab it again for legacy drivers. Unfortunately this means we need to sprinkle a few more #includes around. Also we need to add the drm_device as a parameter to the _END macro. Finally remove the mute_lock() from setcrtc, since that's now done by the macro. Cc: Alex Deucher References: https://gitlab.freedesktop.org/drm/amd/-/issues/1224 Fixes: 9bcaa3fe58ab ("drm: Replace drm_modeset_lock/unlock_all with DRM_MODESET_LOCK_ALL_* helpers") Cc: Michal Orzel Cc: Daniel Vetter Cc: Maarten Lankhorst Cc: Maxime Ripard Cc: Thomas Zimmermann Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Cc: # v5.8+ Signed-off-by: Daniel Vetter Reviewed-by: Alex Deucher Signed-off-by: Alex Deucher Link: https://patchwork.freedesktop.org/patch/msgid/20200814093842.3048472-1-daniel.vetter@ffwll.ch

drm: Add drm_modeset_lock_assert_held()

2019-09-19T18:37:59Z

Add a small wrapper around lockdep_assert_held() to make it a bit more conventinet to use with modeset locks. Signed-off-by: Ville Syrjälä Link: https://patchwork.freedesktop.org/patch/msgid/20190708125325.16576-2-ville.syrjala@linux.intel.com Reviewed-by: Juha-Pekka Heikkila

drm: Trivial comment grammar cleanups

2019-02-04T09:21:17Z

Most of these are just cases where code comments used contractions (it's, who's) where they actually mean to use a possessive pronoun (its, whose) or vice-versa. Signed-off-by: Matt Roper Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20190202012326.20096-1-matthew.d.roper@intel.com

drm: Add DRM_MODESET_LOCK_BEGIN/END helpers

2018-11-29T15:48:31Z

This patch adds a couple of helpers to remove the boilerplate involved in grabbing all of the modeset locks. I've also converted the obvious cases in drm core to use the helpers. The only remaining instance of drm_modeset_lock_all_ctx() is in drm_framebuffer. It's complicated by the state clear that occurs on deadlock. ATM, there's no way to inject code in the deadlock path with the helpers, so it's unfit for conversion. Changes in v2: - Relocate ret argument to the end of the list (Daniel) - Incorporate Daniel's doc suggestions (Daniel) Suggested-by: Daniel Vetter Reviewed-by: Daniel Vetter Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20181129150423.239081-4-sean@poorly.run

drm/atomic: Prepare drm_modeset_lock infrastructure for interruptible waiting, v2.

2017-09-13T07:50:52Z

When we want to make drm_atomic_commit interruptible, there are a lot of places that call the lock function, which we don't have control over. Rather than trying to convert every single one, it's easier to toggle interruptible waiting per acquire_ctx. If drm_modeset_acquire_init is called with DRM_MODESET_ACQUIRE_INTERRUPTIBLE, then we will perform interruptible waits in drm_modeset_lock and drm_modeset_backoff. Changes since v1: - Fix locking example in drm_modeset_lock.c to be compatible with interruptible waiting (xexaxo) and make it default. Uninterruptible waiting shouldn't happen except in corner cases, but the example will still apply if the flag is removed. - Add drm_modeset_lock_single_interruptible() to documentation. - Fix dead link to removed drm_modeset_lock_interruptible() in drm_modeset_lock(). Signed-off-by: Maarten Lankhorst Reviewed-by: Daniel Vetter #v1 Cc: Emil Velikov Link: https://patchwork.freedesktop.org/patch/msgid/20170912133749.6532-2-maarten.lankhorst@linux.intel.com Reviewed-by: Emil Velikov

drm: Remove drm_modeset_legacy_acquire_ctx and crtc->acquire_ctx

2017-04-05T07:26:45Z

With all the callers of drm_modeset_lock_crtc gone, and all the places it was formerly used properly wiring the acquire ctx through, we can remove this. The only hidden context magic we still have is now the global one. Reviewed-by: Harry Wentland Reviewed-by: Maarten Lankhorst Signed-off-by: Daniel Vetter Link: http://patchwork.freedesktop.org/patch/msgid/20170403083304.9083-4-daniel.vetter@ffwll.ch