[Intel-gfx] [PATCH] drm/i915/sprite: Avoid incurring extra vblank stall when updating plane on IVB

[Jesse Barnes]

On Wed, 18 Apr 2012 17:12:26 +0100
Chris Wilson <chris at chris-wilson.co.uk> wrote:

> IvyBridge requires an extra frame between disabling the low power
> watermarks and enabling scaling on the sprite plane. If the scaling
> is already enabled, then we have already disabled the low power
> watermarks and need not incur an extra wait.
> 
> Similarly, as we disable the scaling when turning off the sprite plane,
> we can update the scaling enabled flag and restore the low power
> watermarks.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Jesse Barnes <jbarnes at virtuousgeek.org>
> ---

Yep, this is a good optimization.

Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>

-- 
Jesse Barnes, Intel Open Source Technology Center