Re: [PATCH] drm/xe: Upgrade complaint about missing slice info

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Fri, Jan 17, 2025 at 04:54:03PM -0800, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
> 
> The steering code needs to know slice/subslice counts and this
> information should be retrieved from the hwconfig table. However,
> earlier platforms don't have it, hence the KMD has a fallback path.
> Newer platforms really should have the entries and if they are missing
> that is a bug that needs to be fixed in the table.
> 
> So update the complaint to be an error on newer platforms and remove
> it completely for older ones that we know are bad (but are not POR for
> the Xe driver anyway). Also, re-word the message a little to make it
> clearer what the issue is.
> 
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
> ---
>  drivers/gpu/drm/xe/xe_gt_mcr.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_gt_mcr.c b/drivers/gpu/drm/xe/xe_gt_mcr.c
> index a1676b787fdc..605aad3554e7 100644
> --- a/drivers/gpu/drm/xe/xe_gt_mcr.c
> +++ b/drivers/gpu/drm/xe/xe_gt_mcr.c
> @@ -341,7 +341,13 @@ static unsigned int dss_per_group(struct xe_gt *gt)
>  	return DIV_ROUND_UP(max_subslices, max_slices);
>  
>  fallback:
> -	xe_gt_dbg(gt, "GuC hwconfig cannot provide dss/slice; using typical fallback values\n");
> +	/*
> +	 * Some older platforms don't have tables or don't have complete tables.
> +	 * Newer platforms should always have the required info.
> +	 */
> +	if (GRAPHICS_VERx100(gt_to_xe(gt)) >= 2000)
> +		xe_gt_err(gt, "Slice/Subslice counts missing from hwconfig table; using typical fallback values\n");
> +

is the information useless on older platform? Shouldn't we keep that as
informative at least?

>  	if (gt_to_xe(gt)->info.platform == XE_PVC)
>  		return 8;
>  	else if (GRAPHICS_VERx100(gt_to_xe(gt)) >= 1250)
> -- 
> 2.47.0
>