[Intel-gfx] drm/i915: Agressive downclocking on Baytrail

[Jesse Barnes]

On 01/06/2016 11:15 AM, Janne Heikkinen wrote:
> I've got Bay Trail based Asus X553MA and I've been experiencing daily hangs
> with kernels beginning from 4.2-rc1. I haven't had any problems with 4.1.x
> kernels and using 4.1.13 I've gotten constant 5+ day uptimes since November
> (I had to at least suspend it once per week for traveling but during Christmas
> longest uptime was 11 days).
> 
> Now I did bisection beginning with marking 4.2-rc1 as bad and 4.1.0 as good
> and found out that it was this commit:
> 
> [8fb55197e64d5988ec57b54e973daeea72c3f2ff]
> drm/i915: Agressive downclocking on Baytrail
> 
> causing the hangs.
> 
> 4.4-rc8 hanged in less than hour. After I reversed the patch from it and
> commented out lines containing related fields from i915_debugfs.c
> I now seem to have stable 4.4-rc8.

Cc'ing Deepak and Chris.

Jesse