drm/i915: refactor error detection & collection

This patch refactors the existing error detection and collection code,
placing most of it in i915_handle_error(). Additionally, we introduce a
work queue for scheduling post-crash tasks such as generating a uevent.
Using the uevent facility, userspace should be able to capture a
post-mortem dump for diagnostics.

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ben Gamari <bgamari.foss@gmail.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d087528..b05b44d 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -229,6 +229,7 @@
 
 	spinlock_t error_lock;
 	struct drm_i915_error_state *first_error;
+	struct work_struct error_work;
 
 	/* Register state */
 	u8 saveLBB;