[Intel-gfx] [PATCH 3/5] drm/i915/guc: Use correct error code for GuC initialization failure

[Michal Wajdeczko]

Since commit 6ca9a2beb5 ("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 121981fafe ("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.

Fix that by always returning -EIO on uC hardware related failure.

Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Michal Winiarski <michal.winiarski at intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble at intel.com>
---
 drivers/gpu/drm/i915/intel_uc.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_uc.c b/drivers/gpu/drm/i915/intel_uc.c
index 3a13cbb..1547e16 100644
--- a/drivers/gpu/drm/i915/intel_uc.c
+++ b/drivers/gpu/drm/i915/intel_uc.c
@@ -432,11 +432,8 @@ int intel_uc_init_hw(struct drm_i915_private *dev_priv)
 	 * Note that there is no fallback as either user explicitly asked for
 	 * the GuC or driver default option was to run with the GuC enabled.
 	 */
-	if (GEM_WARN_ON(ret == -EIO))
-		ret = -EINVAL;
-
 	dev_err(dev_priv->drm.dev, "GuC initialization failed %d\n", ret);
-	return ret;
+	return -EIO; /* We want to disable GPU submission but keep KMS alive */
 }
 
 void intel_uc_fini_hw(struct drm_i915_private *dev_priv)
-- 
1.9.1