[Intel-gfx] [PATCH] Revert "drm/i915: Make prepare_plane_fb fully interruptible."

[Maarten Lankhorst]

Hey,

Op 30-10-15 om 22:06 schreef ville.syrjala at linux.intel.com:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
> This reverts commit b26a6b35581c84124bd78b68cc02d171fbd572c9.
>
> commit b26a6b35581c ("drm/i915: Make prepare_plane_fb fully interruptible.")
> breaks GPU reset on gen3/4 machines. Go back to to non-interruptible.
>
I've done some digging and by forcing an unconditional modeset during reset I was able to trigger it on my system. It should be fixed by applying the rest of the interruptible
series so we can mask EIO, followed by replacing i915_mutex_lock_interruptible with mutex_lock_interruptible so there will be no waiting for gpu reset.
This is what's causing the deadlock here. :)

~Maarten

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 22c0f8a54053..df6dbbc85855 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3207,9 +3207,11 @@ void intel_prepare_reset(struct drm_device *dev)
 	if (IS_GEN2(dev))
 		return;
 
+#if 0
 	/* reset doesn't touch the display */
 	if (INTEL_INFO(dev)->gen >= 5 || IS_G4X(dev))
 		return;
+#endif
 
 	drm_modeset_lock_all(dev);
 	/*
@@ -3245,7 +3247,12 @@ void intel_finish_reset(struct drm_device *dev)
 		 * FIXME: Atomic will make this obsolete since we won't schedule
 		 * CS-based flips (which might get lost in gpu resets) any more.
 		 */
+#if 0
 		intel_update_primary_planes(dev);
+#else
+		intel_display_resume(dev);
+		drm_modeset_unlock_all(dev);
+#endif
 		return;
 	}
 
@@ -13174,12 +13181,12 @@ static int intel_atomic_prepare_commit(struct drm_device *dev,
 			flush_workqueue(dev_priv->wq);
 	}
 
-	ret = i915_mutex_lock_interruptible(dev);
+	ret = mutex_lock_interruptible(&dev->struct_mutex);
 	if (ret)
 		return ret;
 
 	ret = drm_atomic_helper_prepare_planes(dev, state);
-	if (!ret && !async) {
+	if (!ret && !async && !i915_reset_in_progress(&dev_priv->gpu_error)) {
 		u32 reset_counter;
 
 		reset_counter = atomic_read(&dev_priv->gpu_error.reset_counter);