[PATCH v2 0/6] Remove I915_ENGINE_FIRST_RENDER_COMPUTE

[Lucas De Marchi]

On Thu, Mar 27, 2025 at 12:39:59AM +0100, Andi Shyti wrote:
>Hi,
>
>While testing the multi-CCS static load balancing, Arshad
>discovered that the CCS workaround was being applied twice, due
>to commit [*].
>
>Further discussions with Lucas led to rethinking the purpose of
>I915_ENGINE_FIRST_RENDER_COMPUTE. This flag was originally
>introduced to handle platforms with different CCS/RCS setups.
>However, for all GPUs currently supported by i915, we can assume
>the presence of at least one RCS engine, so the logic can shift
>to focus on the first CCS engine.

Not sure I follow this... The WAs in "first render or compute" are for
things that are shared between RCS and CCS in the hardware. Why are
shifting the focus to "first CCS engine" when that one can be fused
off/unavailable rather then doing the simple "always do these WAs in the
RCS since that one is always available". And yes, if unofficial support
for PVC is desired, then that can't be done, but shifting it to be
always on CCS would be wrong too.

Lucas De Marchi