drm/i915: Eliminate race from gen2/3 page flip interrupt handling

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If the interrupt handler were to process a previous vblank interrupt and
the following flip pending interrupt at the same time, the page flip
would be completed too soon.

To eliminate this race, check the live pending flip status from the ISR
register before finishing the page flip.

v2: Added a comment explaining the logic (by Chris Wilson)
v3: Fix a typo in the comment

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

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Ville Syrjälä 2013-02-19 15:16:38 +02:00 • committed by Daniel Vetter

parent 2ec90668e3

commit 5e2032d47a

1 changed files with 21 additions and 6 deletions

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drivers/gpu/drm/i915/i915_irq.c

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