Unverified Commit 7908632f authored by Maíra Canal's avatar Maíra Canal Committed by Maíra Canal
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Revert "drm/vkms: Fix race-condition between the hrtimer and the atomic commit" 

This reverts commit a0e6a017.

Unlocking a mutex in the context of a hrtimer callback is violating mutex
locking rules, as mutex_unlock() from interrupt context is not permitted.

Link: https://lore.kernel.org/dri-devel/ZQLAc%2FFwkv%2FGiVoK@phenom.ffwll.local/T/#t


Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarMaíra Canal <mcanal@igalia.com>
Signed-off-by: default avatarMaíra Canal <mairacanal@riseup.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20230914102024.1789154-1-mcanal@igalia.com
parent c900529f

drivers/gpu/drm/vkms/vkms_composer.c

+2 −7
Original line number Diff line number Diff line
@@ -408,15 +408,10 @@ void vkms_set_composer(struct vkms_output *out, bool enabled) 
	if (enabled)

		drm_crtc_vblank_get(&out->crtc);



	mutex_lock(&out->enabled_lock);

	spin_lock_irq(&out->lock);

	old_enabled = out->composer_enabled;

	out->composer_enabled = enabled;



	/* the composition wasn't enabled, so unlock the lock to make sure the lock

	 * will be balanced even if we have a failed commit

	 */

	if (!out->composer_enabled)

		mutex_unlock(&out->enabled_lock);

	spin_unlock_irq(&out->lock);



	if (old_enabled)

		drm_crtc_vblank_put(&out->crtc);

drivers/gpu/drm/vkms/vkms_crtc.c

+4 −5
Original line number Diff line number Diff line
@@ -16,7 +16,7 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer) 
	struct drm_crtc *crtc = &output->crtc;

	struct vkms_crtc_state *state;

	u64 ret_overrun;

	bool ret, fence_cookie, composer_enabled;

	bool ret, fence_cookie;



	fence_cookie = dma_fence_begin_signalling();
@@ -25,15 +25,15 @@ static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer) 
	if (ret_overrun != 1)

		pr_warn("%s: vblank timer overrun\n", __func__);



	spin_lock(&output->lock);

	ret = drm_crtc_handle_vblank(crtc);

	if (!ret)

		DRM_ERROR("vkms failure on handling vblank");



	state = output->composer_state;

	composer_enabled = output->composer_enabled;

	mutex_unlock(&output->enabled_lock);

	spin_unlock(&output->lock);



	if (state && composer_enabled) {

	if (state && output->composer_enabled) {

		u64 frame = drm_crtc_accurate_vblank_count(crtc);



		/* update frame_start only if a queued vkms_composer_worker()
@@ -295,7 +295,6 @@ int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc, 


	spin_lock_init(&vkms_out->lock);

	spin_lock_init(&vkms_out->composer_lock);

	mutex_init(&vkms_out->enabled_lock);



	vkms_out->composer_workq = alloc_ordered_workqueue("vkms_composer", 0);

	if (!vkms_out->composer_workq)

drivers/gpu/drm/vkms/vkms_drv.h

+1 −3
Original line number Diff line number Diff line
@@ -108,10 +108,8 @@ struct vkms_output { 
	struct workqueue_struct *composer_workq;

	/* protects concurrent access to composer */

	spinlock_t lock;

	/* guarantees that if the composer is enabled, a job will be queued */

	struct mutex enabled_lock;



	/* protected by @enabled_lock */

	/* protected by @lock */

	bool composer_enabled;

	struct vkms_crtc_state *composer_state;