drm/i915: Use PM QoS to prevent C-State starvation of gen3 GPU

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945 class hardware has an interesting quirk in which the vblank
interrupt is not raised if the CPU is in a low power state. (We also
suspect that the memory bus is clocked to the CPU/c-state and not the
GPU so there are secondary starvation issues.) In order to prevent the
most obvious issue of the low of the vblank interrupt (stuttering
compositing that only updates when the mouse is moving) is to install a
PM QoS request to prevent low c-states whilst the GPU is active.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

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Chris Wilson 2011-01-09 12:04:40 +00:00

parent f67a559daa

commit b0b544cd37

2 changed files with 38 additions and 0 deletions

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5

drivers/gpu/drm/i915/i915_drv.h

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33

drivers/gpu/drm/i915/i915_irq.c

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