[Intel-gfx] [PATCH 4/4] drm/i915/uc: Use -EIO code for GuC initialization failures

[Chris Wilson]

Quoting Michal Wajdeczko (2019-08-11 20:51:32)
> Since commit 6ca9a2beb54a ("drm/i915: Unwind i915_gem_init() failure")
> we believed that we correctly handle all errors encountered during
> GuC initialization, including special one that indicates request to
> run driver with disabled GPU submission (-EIO).
> 
> Unfortunately since commit 121981fafe69 ("drm/i915/guc: Combine
> enable_guc_loading|submission modparams") we stopped using that
> error code to avoid unwanted fallback to execlist submission mode.
> 
> In result any GuC initialization failure was treated as non-recoverable
> error leading to driver load abort, so we could not even read related
> GuC error log to investigate cause of the problem.
> 
> For now always return -EIO on any uC hardware related failure.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>

Works for me,
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris