[Intel-gfx] [PATCH v2 01/16] drm/i915: Keep vblank interrupts enabled while enabling/disabling planes

[Ville Syrjälä]

On Wed, Jun 04, 2014 at 11:30:47AM +0530, Arun Murthy wrote:
> On Mon, May 26, 2014 at 7:26 PM, Daniel Vetter <daniel at ffwll.ch> wrote:
> > On Thu, May 22, 2014 at 05:48:06PM +0300, ville.syrjala at linux.intel.com wrote:
> >> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >>
> >> Because of the upcoming vblank interrupt driven watermark update
> >> mechanism we will have use for vblank interrupts during plane
> >> enabling/disabling. So don't call drm_vblank_off() until planes
> >> are off, and call drm_vblank_on() just before we start to enable
> >> the planes.
> 
> Since watermark and display control registers are double buffered
> both of them get updated on next blank and hence in sync.
> Can you let me know the need for vblank driven watermark updates?

Watermark registers aren't double buffered.

-- 
Ville Syrjälä
Intel OTC