[PATCH 01/12] drm/xe: Fix MOCS debugfs LNCF readout

[Matt Roper]

On Fri, Feb 21, 2025 at 10:17:20AM +0000, Tvrtko Ursulin wrote:
> With only XE_FW_GT taken LNCF registers read back as all zeroes, leading
> to a wild goose chase trying to figure out why is register programming
> incorrect.
> 
> Fix it by grabbing XE_FORCEWAKE_ALL for affected platforms.

LNCF MOCS registers were only in the render power domain on the old
Xe_LP platforms.  From Xe_HP onward they moved into the GT power domain
(and then in Xe2 they were removed completely).


Matt

> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
> ---
>  drivers/gpu/drm/xe/xe_mocs.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_mocs.c b/drivers/gpu/drm/xe/xe_mocs.c
> index 54d199b5cfb2..31dade91a089 100644
> --- a/drivers/gpu/drm/xe/xe_mocs.c
> +++ b/drivers/gpu/drm/xe/xe_mocs.c
> @@ -781,7 +781,9 @@ void xe_mocs_dump(struct xe_gt *gt, struct drm_printer *p)
>  	flags = get_mocs_settings(xe, &table);
>  
>  	xe_pm_runtime_get_noresume(xe);
> -	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
> +	fw_ref = xe_force_wake_get(gt_to_fw(gt),
> +				   flags & HAS_LNCF_MOCS ?
> +				   XE_FORCEWAKE_ALL : XE_FW_GT);
>  	if (!fw_ref)
>  		goto err_fw;
>  
> -- 
> 2.48.0
> 

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