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Commit 9908ff73 authored by Chris Wilson's avatar Chris Wilson Committed by Eric Anholt
Browse files

drm/i915: Kill dangerous pending-flip debugging 

We can, by virtue of a vblank interrupt firing in the middle of setting
up the unpin work (i.e. after we set the unpin_work field and before we
write to the ringbuffer) enter intel_finish_page_flip() prior to
receiving the pending flip notification. Therefore we can expect to hit
intel_finish_page_flip() under normal circumstances without a pending flip
and even without installing the pending_flip_obj. This is exacerbated by
aperture thrashing whilst binding the framebuffer

References:

  Bug 28079 - "glresize" causes kernel panic in intel_finish_page_flip.
  https://bugs.freedesktop.org/show_bug.cgi?id=28079



Reported-by: default avatarNick Bowler <nbowler@draconx.ca>
Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@kernel.org
Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: default avatarEric Anholt <eric@anholt.net>
parent f1befe71

drivers/gpu/drm/i915/intel_display.c

+0 −6
Original line number Diff line number Diff line
@@ -4589,12 +4589,6 @@ void intel_finish_page_flip(struct drm_device *dev, int pipe) 
	spin_lock_irqsave(&dev->event_lock, flags);

	work = intel_crtc->unpin_work;

	if (work == NULL || !work->pending) {

		if (work && !work->pending) {

			obj_priv = to_intel_bo(work->pending_flip_obj);

			DRM_DEBUG_DRIVER("flip finish: %p (%d) not pending?\n",

					 obj_priv,

					 atomic_read(&obj_priv->pending_flip));

		}

		spin_unlock_irqrestore(&dev->event_lock, flags);

		return;

	}