[PATCH] drm/atomic: only run atomic_check() if crtc is active

[Gustavo Padovan]

Hi Ville,

2015-11-13 Ville Syrjälä <ville.syrjala at linux.intel.com>:

> On Fri, Nov 13, 2015 at 11:45:58AM -0200, Gustavo Padovan wrote:
> > From: Gustavo Padovan <gustavo.padovan at collabora.co.uk>
> > 
> > Fixes an regression added by 3ae2436 (drm/exynos/mixer: replace
> > direct cross-driver call with drm mode) and while this regression was
> > caused by a change in the exynos driver it makes sense to add the
> > check on atomic core to benefit other drivers as well.
> > 
> > The whole atomic update fails if the exynos hdmi display is not
> > present/active.  Add a test to only run atomic_check() if the CRTC is
> > active.
> 
> The check must be performed even when the crtc is not active.
> 
> Especially important for the (enabled && !active) case (ie. DPMS off)
> since "DPMS on" must not fail, so any state change while in DPMS off
> must be checked as if the crtc was active.
> 
> But even for the !enabled case we want to do the check so that
> everything gets properly recomputed when fully disabling a crtc.

You are right. I'll fix this locally in exynos for now.

	Gustavo