Re: [PATCH 1/2] drm/xe/huc: Adjust HuC check on primary GT

[Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>]

On 9/18/2025 2:13 PM, Matt Roper wrote:
> The HuC initialization code determines whether a platform can have a HuC
> on the primary GT by checking whether tile->media_gt is NULL; old Xe1
> platforms that combined render+media into a single GT will always have a
> NULL media_gt pointer.  However once we allow media to be disabled via
> configfs, there will also be cases where tile->media_gt is NULL on more
> modern platforms, causing this condition to behave incorrectly.
>
> To handle cases where media gets disabled via configfs (or theoretical
> cases where media is truly fused off in hardware), change the condition
> to consider the graphics version of the primary GT; only the old Xe1
> platforms with graphics versions 12.55 or earlier should try to
> initialize a HuC on the primary GT.
>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
> ---
>   drivers/gpu/drm/xe/xe_huc.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_huc.c b/drivers/gpu/drm/xe/xe_huc.c
> index 7e43b2dd6a32..0a70c8924582 100644
> --- a/drivers/gpu/drm/xe/xe_huc.c
> +++ b/drivers/gpu/drm/xe/xe_huc.c
> @@ -66,14 +66,18 @@ static int huc_alloc_gsc_pkt(struct xe_huc *huc)
>   int xe_huc_init(struct xe_huc *huc)
>   {
>   	struct xe_gt *gt = huc_to_gt(huc);
> -	struct xe_tile *tile = gt_to_tile(gt);
>   	struct xe_device *xe = gt_to_xe(gt);
>   	int ret;
>   
>   	huc->fw.type = XE_UC_FW_TYPE_HUC;
>   
> -	/* On platforms with a media GT the HuC is only available there */
> -	if (tile->media_gt && (gt != tile->media_gt)) {
> +	/*
> +	 * The HuC is only available on the media GT on most platforms.  The
> +	 * exception to that rule are the old Xe1 platforms where there was
> +	 * no separate GT for media IP, so the HuC was part of the primary
> +	 * GT.  Such platforms have graphics versions 12.55 and earlier.
> +	 */
> +	if (!xe_gt_is_media_type(gt) && GRAPHICS_VERx100(xe) > 1255) {

Since we can now match a FW definition to a specific GT in the FW table, 
we could change the HuC FW defs for MTL+ from GT_TYPE_ANY to 
GT_TYPE_MEDIA and just remove this check here entirely. Just a thought, 
not a blocker.

Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>

Daniele

>   		xe_uc_fw_change_status(&huc->fw, XE_UC_FIRMWARE_NOT_SUPPORTED);
>   		return 0;
>   	}