[PATCH] drm/xe/guc: Enable WA_DUAL_QUEUE for newer platforms

[Narvaez, Jesus]

Looks good to me.

Reviewed-by: Jesus Narvaez <jesus.narvaez at intel.com>

- Jesus Narvaez

On 11/26/2024 5:11 PM, Daniele Ceraolo Spurio wrote:
> The DUAL_QUEUE_WA tells the GuC to not allow concurrent submissions
> on RCS and CCSes with different address spaces, which on DG2 is
> required as a WA for an HW bug. On newer platforms, this block has
> been moved in HW at the CS level, by stalling the RCS/CCS context
> switch when one of the other RCS/CCSes is busy with a different
> address space. While functionally correct, having a submission
> stalled on the HW limits the GuC ability to shuffle things around and
> can cause complications if the non-stalled submission runs for a long
> time, because the GuC doesn't know that the stalled submission isn't
> actually running and might declare it as hung. Therefore, we enable
> the DUAL_QUEUE_WA on all newer platforms to move management back to
> the GuC.
>
> Note that the GuC specs also recommend enabling this for all platforms
> starting from MTL that have a CCS.
>
> Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: John Harrison <John.C.Harrison at Intel.com>
> ---
>   drivers/gpu/drm/xe/xe_guc.c | 16 +++++++++++++++-
>   1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index df1ba94cf4ca..ddbfbdf901b0 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -151,7 +151,21 @@ static u32 guc_ctl_wa_flags(struct xe_guc *guc)
>   	if (XE_WA(gt, 14014475959))
>   		flags |= GUC_WA_HOLD_CCS_SWITCHOUT;
>   
> -	if (XE_WA(gt, 22011391025))
> +	/*
> +	 * The DUAL_QUEUE_WA tells the GuC to not allow concurrent submissions
> +	 * on RCS and CCSes with different address spaces, which on DG2 is
> +	 * required as a WA for an HW bug. On newer platforms, this block has
> +	 * been moved in HW at the CS level, by stalling the RCS/CCS context
> +	 * switch when one of the other RCS/CCSes is busy with a different
> +	 * address space. While functionally correct, having a submission
> +	 * stalled on the HW limits the GuC ability to shuffle things around and
> +	 * can cause complications if the non-stalled submission runs for a long
> +	 * time, because the GuC doesn't know that the stalled submission isn't
> +	 * actually running and might declare it as hung. Therefore, we enable
> +	 * the DUAL_QUEUE_WA on all newer platforms to move management back to
> +	 * the GuC.
> +	 */
> +	if (XE_WA(gt, 22011391025) || GRAPHICS_VERx100(xe) >= 1270)
>   		flags |= GUC_WA_DUAL_QUEUE;
>   
>   	/*