[Intel-gfx] [PATCH v4 02/22] drm/i915/guc: Don't allow GuC submission

[Joonas Lahtinen]

Quoting Michal Wajdeczko (2019-05-24 02:30:29)
> Due to the upcoming changes to the GuC ABI interface, we must
> disable GuC submission mode until final ABI will be available
> on all GuC firmwares.
> 
> To avoid regressions on systems configured to run with no longer
> supported configuration "enable_guc=3" or "enable_guc=1" clear
> GuC submission bit.
> 
> v2: force switch to non-GuC submission mode
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: John Spotswood <john.a.spotswood at intel.com>
> Cc: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> Cc: Tony Ye <tony.ye at intel.com>
> Cc: Anusha Srivatsa <anusha.srivatsa at intel.com>
> Cc: Jeff Mcgee <jeff.mcgee at intel.com>
> Cc: Antonio Argenziano <antonio.argenziano at intel.com>
> Cc: Sujaritha Sundaresan <sujaritha.sundaresan at intel.com>
> Cc: Martin Peres <martin.peres at linux.intel.com>
> Acked-by: Martin Peres <martin.peres at linux.intel.com>

> diff --git a/drivers/gpu/drm/i915/intel_uc.c b/drivers/gpu/drm/i915/intel_uc.c
> index 1a265fbd95c7..f66105d756df 100644
> --- a/drivers/gpu/drm/i915/intel_uc.c
> +++ b/drivers/gpu/drm/i915/intel_uc.c
> @@ -298,6 +307,10 @@ int intel_uc_init(struct drm_i915_private *i915)
>         if (!HAS_GUC(i915))
>                 return -ENODEV;
>  
> +       /* XXX: GuC submission is unavailable for now */
> +       if (USES_GUC_SUBMISSION(i915))
> +               return -EIO;
> +

This would be a driver programmer error, wouldn't it?

Maybe add GEM_BUG_ON() to the later branch that does the check?

Regards, Joonas