[Intel-gfx] [PATCH 3/4] drm/i915: Drop the excessive vblank waits from modeset codepaths

[Chris Wilson]

On Wed, Mar 12, 2014 at 11:16:59AM +0200, Ville Syrjälä wrote:
> On Wed, Mar 12, 2014 at 08:35:39AM +0000, Chris Wilson wrote:
> > On Tue, Mar 11, 2014 at 07:37:35PM +0200, ville.syrjala at linux.intel.com wrote:
> > > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > 
> > > Now that we've plugged the mmio vs. ring flip race, we shouldn't need
> > > these vblank waits in the modeset codepaths anymore. So get rid of
> > > them.
> > 
> > Hmm, could we not add an assert(DSPSURFLIVE ==
> > intel_crtc->dspsurf)?
> 
> Where would you want the assert?

assert_plane_is_bound(new_fb) in crtc_enable() and
assert_plane_is_bound(old_fb) in crt_disable(). i.e. add them to our set
of plane/pipe checks through modeset.

Extra paranoia would be to double check dspsurflive against dspsurf
during KMS init.
 
> > And maybe start tracking the frame counters?
> 
> Tracking them for what purpose?

Just general debug, checking modesets trigger an update. Fun stats.
No clear purpose yet, but if we had it exposed in a debugfs file (say
i915_display_info) we are more likely to remember it is available when
required.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre