[Intel-gfx] [PATCH] drm/i915: Restore sane defaults for KMS on GEM error load

[Chris Wilson]

If we fail during GEM initialisation, we scrub the HW state by
performing a device level GPU resuet. However, we want to leave the
system in a usable state (with functioning KMS but no GEM) so after
scrubbing the HW state, we need to restore some sane defaults and
re-enable the low-level common parts of the GPU (such as the GMCH).

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index a4031fab57b0..2b93fdd5a7a6 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -5608,7 +5608,10 @@ int i915_gem_init(struct drm_i915_private *dev_priv)
 					"Failed to initialize GPU, declaring it wedged!\n");
 			i915_gem_set_wedged(dev_priv);
 		}
-		ret = 0;
+
+		/* Minimal basic recovery for KMS */
+		ret = i915_ggtt_enable_hw(dev_priv);
+		intel_init_clock_gating(dev_priv);
 	}
 
 	i915_gem_drain_freed_objects(dev_priv);
-- 
2.18.0