[Intel-gfx] [PATCH] drm/i915: FBC flush nuke for BDW

[Daniel Vetter]

On Fri, Sep 05, 2014 at 02:12:49PM -0700, Rodrigo Vivi wrote:
> As Paulo told the part 2 of his proposal is still missing and we will get
> the WARN of reading fbc register at fbc_enabled when on runtime_suspend...
> 
> But I couldn't find the propper place to check for intel_crtc->active. This
> was another issue reported by power team that on screen off there was to
> much activity on our driver. So we need to check it more carefully the
> proper place to avoid all unecessary inactivities with display off.
> 
> Do you have any suggestion Daniel?

Don't check for intel->active since doing that will lead to hilarious
locking inversions. You have to add a bit of tracking (with it's own
locking) for which frontbuffer events are interesting for fbc like psr
does. Since we only do fbc on one plane ever that's only ever going to be
one bit, but setting/clearing it correctly in crtc_enable/disable is the
important part here.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch