Re: [PATCH v4] drm/i915 : Added Programming of the MOCS

Chris Wilson
2015-06-18T07:42:27Z

On Thu, Jun 18, 2015 at 08:59:55AM +0200, Daniel Vetter wrote:
> > + /*
> > + * Failing to program the MOCS is non-fatal.The system will not
> > + * run at peak performance. So generate a warning and carry on.
> > + */
>
> Is this really true? Userspace must make sure that they don't
> inappropriately overwrite the caching settings using MOCS for frontbuffers
> and in doing so causing coherency issues with the display block. If we
> fail to program MOCS correctly then things won't look pretty.

I was under the presumption that the MOCS entries would default to UC,
since that is the failsafe mode.
-Chris

--
Chris Wilson, Intel Open Source Technology Centre