[Intel-gfx] [PATCH] drm/i915/guc: Don't read SOFT_SCRATCH(15) on MMIO error

[Chris Wilson]

Quoting Michal Wajdeczko (2018-05-28 18:16:18)
> SOFT_SCRATCH(15) is used by GuC for sending MMIO GuC events to host and
> those events are now handled by intel_guc_to_host_event_handler_mmio().
> 
> We should not try to read it on MMIO action error as 1) we may be using
> different set of registers for GuC MMIO communication, and 2) GuC may
> use CTB mechanism for sending events to host.
> 
> While here, upgrade error message to DRM_ERROR.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Michel Thierry <michel.thierry at intel.com>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>

I'm still not totally sold on having the DRM_ERROR here improves
debugging; it doesn't do anything to improve error handling, but

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

nevertheless.
-Chris