[PATCH] drm/xe/xe2lpg: Extend Wa_14020338487

[Lucas De Marchi]

On Wed, Apr 17, 2024 at 06:45:47PM GMT, Gustavo Sousa wrote:
>Quoting Gustavo Sousa (2024-04-17 18:25:01-03:00)
>>Wa_14020338487 also applies to Xe2_LPG. Replicate the existing entry to
>>one specific for Xe2_LPG.
>
>I would also like to take this as an opportunity to discuss the way we
>are currently arranging the RTP entries for the workaround. Using this
>one as example, created a copy of the entry and edited the argument of
>GRAPHICS_VERSION() to match Xe2_LPG. There are multiple cases already
>following the same pattern, mainly because we are grouping entries by
>IP release.
>
>Do we want to continue following that pattern and keep the code
>duplication? Or should we think of a way to avoid code duplication here?
>
>A very simple approach that I think of is having a single entry for each
>lineage. But I guess that's not really feasible today because I guess we
>do not have a way of expressing logical disjunction in XE_RTP_RULES().

yes, implementing it was always something I considered, but then there
was also the fact that when we have WAs that are on IPs that are not
close to each other we may have subtle differences like registers with
different offset or mcr vs non-mcr.

There's also the implementation side: implementing the OR probably means
increasing the size for every item so some of them can have ORed rules.

The other option that I was considering was to eventually split
the rules from the actions and follow a similar scheme to what was done
in drivers/gpu/drm/xe/xe_wa_oob.rules (but generating a table rather
than the current xe_wa.oob.c). The positive side is that we free
ourselves from having to implement things in CPP. I'd probably gone
that direction if xe_wa_oob had been done before the rest.

Lucas De Marchi