[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.

Ok.
 
> While here, upgrade error message to DRM_ERROR.

Does the error help? What do you want to convey to the user? For error
handling, we want to propagate the result back anyway for the caller has
to decide what to do next.
-Chris