[Intel-gfx] [PATCH] drm/i915: Fix cdclk vs. dev_cdclk mess when not recomputing things

[Ville Syrjälä]

On Fri, Oct 28, 2016 at 11:05:48PM +0200, Paul Bolle wrote:
> On Fri, 2016-10-28 at 19:59 +0300, ville.syrjala at linux.intel.com wrote:
> > Fixes: 1a617b77658e ("drm/i915: Keep track of the cdclk as if all crtc's were active.")
> 
> Obviously, I'm pretty happy with this patch. One question though: this
> fixes a commit that shipped in v4.6. Do you have any idea why this
> issue apparently never surfaced before v4.8?

Pop quiz time, eh? :)

I think it was probably due to

commit 44d1240d006c9cd0249263b5449c8e4752500f6a
Author: Marek Szyprowski <m.szyprowski at samsung.com>
Date:   Mon Jun 13 11:11:26 2016 +0200

    drm: add generic zpos property

If you want want to grade my answer all you have to do is revert that
on 4.8 and see what happens. Might be interesting to see if I'm right
actually since the link between the WARN and that commit isn't entirely
obvious.

-- 
Ville Syrjälä
Intel OTC