Re: [PATCH v6 2/3] drm/i915/gt: Do not generate the command streamer for all the CCS

Hi Matt,

On Tue, Mar 26, 2024 at 09:03:10AM -0700, Matt Roper wrote:

On Wed, Mar 13, 2024 at 09:19:50PM +0100, Andi Shyti wrote:

...

• 	/*
  

• 	 * Do not create the command streamer for CCS slices
  

• 	 * beyond the first. All the workload submitted to the
  

• 	 * first engine will be shared among all the slices.
  

• 	 *
  

• 	 * Once the user will be allowed to customize the CCS
  

• 	 * mode, then this check needs to be removed.
  

• 	 */
  

• 	if (IS_DG2(i915) &&
  

• 	    class == COMPUTE_CLASS &&
  

• 	    ccs_instance++)
  

• 		continue;
  

Wouldn't it be more intuitive to drop the non-lowest CCS engines in init_engine_mask() since that's the function that's dedicated to building the list of engines we'll use? Then we don't need to kill the assertion farther down either.

Because we don't check the result of init_engine_mask() while creating the engine's structure. We check it only after and indeed I removed the drm_WARN_ON() check.

I think the whole process of creating the engine's structure in the intel_engines_init_mmio() can be simplified, but this goes beyong the scope of the series.

Or am I missing something?

Thanks, Andi