[Intel-gfx] [PATCH V2] drm/i915/mtl: Add workaround 14018778641

[Matt Roper]

It looks like the number you have in the title and comments isn't a
valid workaround number.  It looks like you actually meant to use
Wa_14018575942.

On Mon, Apr 24, 2023 at 03:47:49PM +0530, Tejas Upadhyay wrote:
> WA 18018781329 is applicable now across all MTL
> steppings.

Wa_18018781329 hasn't changed; it's still restricted to just A-step of
MTL.  What you're implementing here is a different workaround that has
the same implementation, and a broader platform list.  It would be more
accurate to say something like

"Wa_14018575942 is identical to existing Wa_18018781329, but applies to
all MTL steppings."


Matt

> 
> V2:
>   - Remove IS_MTL check, code already running for MTL - Matt
> 
> Cc: Matt Roper <matthew.d.roper at intel.com>
> Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_workarounds.c | 30 ++++++++++-----------
>  1 file changed, 14 insertions(+), 16 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> index 312eb8b5f949..de4f8e2e8e8c 100644
> --- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
> +++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
> @@ -1695,19 +1695,18 @@ pvc_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
>  static void
>  xelpg_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
>  {
> +	/* Wa_14018778641 / Wa_18018781329 */
> +	wa_mcr_write_or(wal, RENDER_MOD_CTRL, FORCE_MISS_FTLB);
> +	wa_mcr_write_or(wal, COMP_MOD_CTRL, FORCE_MISS_FTLB);
> +
>  	if (IS_MTL_GRAPHICS_STEP(gt->i915, M, STEP_A0, STEP_B0) ||
>  	    IS_MTL_GRAPHICS_STEP(gt->i915, P, STEP_A0, STEP_B0)) {
>  		/* Wa_14014830051 */
>  		wa_mcr_write_clr(wal, SARB_CHICKEN1, COMP_CKN_IN);
>  
> -		/* Wa_18018781329 */
> -		wa_mcr_write_or(wal, RENDER_MOD_CTRL, FORCE_MISS_FTLB);
> -		wa_mcr_write_or(wal, COMP_MOD_CTRL, FORCE_MISS_FTLB);
> -
>  		/* Wa_14015795083 */
>  		wa_write_clr(wal, GEN7_MISCCPCTL, GEN12_DOP_CLOCK_GATE_RENDER_ENABLE);
>  	}
> -
>  	/*
>  	 * Unlike older platforms, we no longer setup implicit steering here;
>  	 * all MCR accesses are explicitly steered.
> @@ -1718,17 +1717,16 @@ xelpg_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
>  static void
>  xelpmp_gt_workarounds_init(struct intel_gt *gt, struct i915_wa_list *wal)
>  {
> -	if (IS_MTL_MEDIA_STEP(gt->i915, STEP_A0, STEP_B0)) {
> -		/*
> -		 * Wa_18018781329
> -		 *
> -		 * Note that although these registers are MCR on the primary
> -		 * GT, the media GT's versions are regular singleton registers.
> -		 */
> -		wa_write_or(wal, XELPMP_GSC_MOD_CTRL, FORCE_MISS_FTLB);
> -		wa_write_or(wal, XELPMP_VDBX_MOD_CTRL, FORCE_MISS_FTLB);
> -		wa_write_or(wal, XELPMP_VEBX_MOD_CTRL, FORCE_MISS_FTLB);
> -	}
> +	/*
> +	 * Wa_14018778641
> +	 * Wa_18018781329
> +	 *
> +	 * Note that although these registers are MCR on the primary
> +	 * GT, the media GT's versions are regular singleton registers.
> +	 */
> +	wa_write_or(wal, XELPMP_GSC_MOD_CTRL, FORCE_MISS_FTLB);
> +	wa_write_or(wal, XELPMP_VDBX_MOD_CTRL, FORCE_MISS_FTLB);
> +	wa_write_or(wal, XELPMP_VEBX_MOD_CTRL, FORCE_MISS_FTLB);
>  
>  	debug_dump_steering(gt);
>  }
> -- 
> 2.25.1
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation