[Intel-gfx] drm/i915: WARN_ON_ONCE(!crtc_clock || cdclk < crtc_clock)

[Paul Bolle]

[Adding Matt]

On Wed, 2016-10-12 at 14:08 +0300, Joonas Lahtinen wrote:
> Bisecting the offending commit between v4.8 and v4.8.1 would be a good
> start.

0) Why use a personal notebook when one can just post any half baked
idea to lkml?

1) I stumbled on https://bugzilla.redhat.com/show_bug.cgi?id=1361357 (s
ame hardware, rather similar trace).

2) That report was about the first Fedora (rawhide) kernel release
after this commit http://pkgs.fedoraproject.org/cgit/rpms/kernel.git/co
mmit/?h=f25&id=7d2c2f2d91793b5da452bee9bea4fa32051c8608 ("Bring in
patch-series from drm-next to fix skl_update_other_pipe_wm issues").

3) That seventeen part series ended up in v4.8. The last commit of that
series is commit 5b483747a925 ("drm/i915: Remove wm_config from
dev_priv/intel_atomic_state").

4) So, with a little bit of luck, my bisect might only need to look at
those seventeen commits. Still, it will probably be next week before I
have a day or two to actually perform that bisect.

To be continued,


Paul Bolle