Re: [Intel-gfx] [PATCH v8 2/9] drm/i915: Add the gen12_needs_ccs_aux_inv helper

[Nirmoy Das <nirmoy.das@linux.intel.com>]

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On 7/21/2023 6:15 PM, Andi Shyti wrote:
> We always assumed that a device might either have AUX or FLAT
> CCS, but this is an approximation that is not always true, e.g.
> PVC represents an exception.
>
> Set the basis for future finer selection by implementing a
> boolean gen12_needs_ccs_aux_inv() function that tells whether aux
> invalidation is needed or not.
>
> Currently PVC is the only exception to the above mentioned rule.
>
> Signed-off-by: Andi Shyti<andi.shyti@linux.intel.com>
> Cc: Matt Roper<matthew.d.roper@intel.com>
> Cc: Jonathan Cavitt<jonathan.cavitt@intel.com>
> Cc:<stable@vger.kernel.org>  # v5.8+

|Reviewed-by: Nirmoy Das <nirmoy.das@intel.com>|

> ---
>   drivers/gpu/drm/i915/gt/gen8_engine_cs.c | 18 +++++++++++++++---
>   1 file changed, 15 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> index 563efee055602..460c9225a50fc 100644
> --- a/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> +++ b/drivers/gpu/drm/i915/gt/gen8_engine_cs.c
> @@ -165,6 +165,18 @@ static u32 preparser_disable(bool state)
>   	return MI_ARB_CHECK | 1 << 8 | state;
>   }
>   
> +static bool gen12_needs_ccs_aux_inv(struct intel_engine_cs *engine)
> +{
> +	if (IS_PONTEVECCHIO(engine->i915))
> +		return false;
> +
> +	/*
> +	 * so far platforms supported by i915 having
> +	 * flat ccs do not require AUX invalidation
> +	 */
> +	return !HAS_FLAT_CCS(engine->i915);
> +}
> +
>   u32 *gen12_emit_aux_table_inv(struct intel_gt *gt, u32 *cs, const i915_reg_t inv_reg)
>   {
>   	u32 gsi_offset = gt->uncore->gsi_offset;
> @@ -267,7 +279,7 @@ int gen12_emit_flush_rcs(struct i915_request *rq, u32 mode)
>   		else if (engine->class == COMPUTE_CLASS)
>   			flags &= ~PIPE_CONTROL_3D_ENGINE_FLAGS;
>   
> -		if (!HAS_FLAT_CCS(rq->engine->i915))
> +		if (gen12_needs_ccs_aux_inv(rq->engine))
>   			count = 8 + 4;
>   		else
>   			count = 8;
> @@ -285,7 +297,7 @@ int gen12_emit_flush_rcs(struct i915_request *rq, u32 mode)
>   
>   		cs = gen8_emit_pipe_control(cs, flags, LRC_PPHWSP_SCRATCH_ADDR);
>   
> -		if (!HAS_FLAT_CCS(rq->engine->i915)) {
> +		if (gen12_needs_ccs_aux_inv(rq->engine)) {
>   			/* hsdes: 1809175790 */
>   			cs = gen12_emit_aux_table_inv(rq->engine->gt, cs,
>   						      GEN12_CCS_AUX_INV);
> @@ -307,7 +319,7 @@ int gen12_emit_flush_xcs(struct i915_request *rq, u32 mode)
>   	if (mode & EMIT_INVALIDATE) {
>   		cmd += 2;
>   
> -		if (!HAS_FLAT_CCS(rq->engine->i915) &&
> +		if (gen12_needs_ccs_aux_inv(rq->engine) &&
>   		    (rq->engine->class == VIDEO_DECODE_CLASS ||
>   		     rq->engine->class == VIDEO_ENHANCEMENT_CLASS)) {
>   			aux_inv = rq->engine->mask &

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