Revert "drm/i915: Fix races on fbdev"
This reverts commit a7442b93cf32c1e1ddb721a26cd1f92302e2a222.
With the patch applied SNB, IVB and ILK are experiencing hard machine
hangs. Original patch was to fix "just" kernel panics so it's not a good
trade-off.
Proper fix for the panic is on the way, lets revert until then.
Fixes: a7442b93cf32 ("drm/i915: Fix races on fbdev")
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tomi Sarvela <tomi.p.sarvela@intel.com>
Cc: stable@vger.kernel.org
Acked-by: Lukas Wunner <lukas@wunner.de>
Tested-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
Suggested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1459510861-29035-1-git-send-email-joonas.lahtinen@linux.intel.com
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index a66ce49..b377753 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -493,9 +493,11 @@
* Some ports require correctly set-up hpd registers for detection to
* work properly (leading to ghost connected connector status), e.g. VGA
* on gm45. Hence we can only set up the initial fbdev config after hpd
- * irqs are fully enabled. We protect the fbdev initial config scanning
- * against hotplug events by waiting in intel_fbdev_output_poll_changed
- * until the asynchronous thread has finished.
+ * irqs are fully enabled. Now we should scan for the initial config
+ * only once hotplug handling is enabled, but due to screwed-up locking
+ * around kms/fbdev init we can't protect the fdbev initial config
+ * scanning against hotplug events. Hence do this first and ignore the
+ * tiny window where we will loose hotplug notifactions.
*/
intel_fbdev_initial_config_async(dev);