[Intel-xe] [PATCH v3 14/14] drm/xe: Move policy on preemption from WAs to tunings

[Lucas De Marchi]

On Tue, Mar 14, 2023 at 04:46:58PM -0700, Matt Roper wrote:
>On Mon, Mar 13, 2023 at 05:30:12PM -0700, Lucas De Marchi wrote:
>> The fake WA FtrPerCtxtPreemptionGranularityControl is documented in i915
>> and is not a true WA: it's a policy chosen to allow preemption settings
>> to be controlled on a per-context basis by userspace. Move it to
>> xe_tuning.c since it's more in line with what his is doing. However
>> since it's not something suggested by the spec, prefix it with "Policy"
>> rather than "Tuning".
>>
>> Also, there's no reason to apply this policy only between graphics
>> version 1200 and 1250. Apply it to all versions, like i915.
>>
>
>The big mega-comment in i915 was explicitly requested by the i915
>maintainers since the way preemption is controlled is kind of hard to
>follow from the bspec, and there aren't many people around who still
>remember the old discussions about this stuff from a decade ago.  We
>should probably bring at least some of that text over to Xe as a comment
>as well.  We can drop the stuff about gen9, but the explanation of the
>two control options and list of related workarounds is something we
>probably want to preserve.

ok. Since all the others are unblocked on the review side. I'm going to
apply them and come back to this in a "tuning" series where the current
issue you pointed out in patch 13 is fixed and the comment you are
pointing out is also copied over.

thanks for the reviews

Lucas De Marchi