[Intel-gfx] [PATCH v2] drm/i915/mtl: do not enable render power-gating on MTL

[Rodrigo Vivi]

On Thu, May 18, 2023 at 04:50:52PM +0200, Andrzej Hajda wrote:
> Multiple CI tests fails with forcewake ack timeouts if render
> power gating is enabled.
> BSpec 52698 states it should be 0 for MTL, but apparently
> this info is outdated. Anyway since the patch makes MTL pass basic
> tests added FIXME tag informing this is temporary workaround.
> 
> v2: added FIXME tag
> 
> Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4983

No change in the patch is needed, but do we have another
(can be internal) ticket with the work to get this properly
fix without wasting power?

> Signed-off-by: Andrzej Hajda <andrzej.hajda at intel.com>
> Reviewed-by: Nirmoy Das <nirmoy.das at intel.com>
> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com>
> ---
> Changes in v2:
> - added FIXME tag
> - Link to v1: https://lore.kernel.org/r/20230517-mtl_disable_render_pg-v1-1-6495eebbfb24@intel.com
> ---
>  drivers/gpu/drm/i915/gt/intel_rc6.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_rc6.c b/drivers/gpu/drm/i915/gt/intel_rc6.c
> index 908a3d0f2343f4..58bb1c55294c93 100644
> --- a/drivers/gpu/drm/i915/gt/intel_rc6.c
> +++ b/drivers/gpu/drm/i915/gt/intel_rc6.c
> @@ -117,8 +117,14 @@ static void gen11_rc6_enable(struct intel_rc6 *rc6)
>  			GEN6_RC_CTL_RC6_ENABLE |
>  			GEN6_RC_CTL_EI_MODE(1);
>  
> -	/* Wa_16011777198 - Render powergating must remain disabled */
> -	if (IS_DG2_GRAPHICS_STEP(gt->i915, G10, STEP_A0, STEP_C0) ||
> +	/*
> +	 * Wa_16011777198 and BSpec 52698 - Render powergating must be off.
> +	 * FIXME BSpec is outdated, disabling powergating for MTL is just
> +	 * temporary wa and should be removed after fixing real cause
> +	 * of forcewake timeouts.
> +	 */
> +	if (IS_METEORLAKE(gt->i915) ||
> +	    IS_DG2_GRAPHICS_STEP(gt->i915, G10, STEP_A0, STEP_C0) ||
>  	    IS_DG2_GRAPHICS_STEP(gt->i915, G11, STEP_A0, STEP_B0))
>  		pg_enable =
>  			GEN9_MEDIA_PG_ENABLE |
> 
> ---
> base-commit: 641646b29337c97681e0edb67ad2e08aef3fb850
> change-id: 20230517-mtl_disable_render_pg-b9f9f1567f9e
> 
> Best regards,
> -- 
> Andrzej Hajda <andrzej.hajda at intel.com>
>