Re: [PATCH v1 1/1] drm/xe/guc: Do not assert CTB state while sending MMIO

[Michal Wajdeczko <michal.wajdeczko@intel.com>]

On 07.11.2024 16:13, Tomasz Lis wrote:
> During VF post-migration recovery, MMIO communication channel to GuC
> is used, despite CTB channel being enabled. This behavior is rooted
> in the save-restore architecture specification.
> 
> Therefore, a VF driver cannot assert that CTB is disabled while sending
> MMIO messages to GuC. Such assertion needs to be PF only, or be removed.

+ Matt

> 
> This patch simply removes the assertion.
> 
> Signed-off-by: Tomasz Lis <tomasz.lis@intel.com>
> Suggested-by: Michał Wajdeczko <michal.wajdeczko@intel.com>

in fact I was already trying to fix that [1], but I had to wait until we
have some S/R code in place, so I'm fine with it as-is

Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>

[1] https://patchwork.freedesktop.org/series/128721/#rev1

> ---
>  drivers/gpu/drm/xe/xe_guc.c | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
> index 7224593c9ce9..df1ba94cf4ca 100644
> --- a/drivers/gpu/drm/xe/xe_guc.c
> +++ b/drivers/gpu/drm/xe/xe_guc.c
> @@ -945,7 +945,6 @@ int xe_guc_mmio_send_recv(struct xe_guc *guc, const u32 *request,
>  
>  	BUILD_BUG_ON(VF_SW_FLAG_COUNT != MED_VF_SW_FLAG_COUNT);
>  
> -	xe_assert(xe, !xe_guc_ct_enabled(&guc->ct));
>  	xe_assert(xe, len);
>  	xe_assert(xe, len <= VF_SW_FLAG_COUNT);
>  	xe_assert(xe, len <= MED_VF_SW_FLAG_COUNT);