Merge tag 'drm-intel-fixes-2013-11-07' of git://people.freedesktop.org/~danvet/drm-intel into drm-next

Bit a bit -fixes pull request in the merge window than usual dua to two
feauture-y things:
- Display CRCs are now enabled on all platforms, including the odd DP case
  on gm45/vlv. Since this is a testing-only feature it should ever hurt,
  but I figured it'll help with regression-testing -fixes. So I left it
  in and didn't postpone it to 3.14.
- Display power well refactoring from Imre. Would have caused major pain
  conflict with the bdw stage 1 patches if I'd postpone this to -next.
  It's only an relatively small interface rework, so shouldn't cause pain.
  It's also been in my tree since almost 3 weeks already.

That accounts for about two thirds of the pull, otherwise just bugfixes:
- vlv backlight fix from Jesse/Jani
- vlv vblank timestamp fix from Jesse
- improved edp detection through vbt from Ville (fixes a vlv issue)
- eDP vdd fix from Paulo
- fixes for dvo lvds on i830M
- a few smaller things all over

Note: This contains a backmerge of v3.12. Since the -internal branch
always applied on top of -nightly I need that unified base to merge bdw
patches. So you'll get a conflict with radeon connector props when pulling
this (and nouveau/master will also conflict a bit when Ben doesn't
rebase). The backmerge itself only had conflicts in drm/i915.

There's also a tiny conflict between Jani's backlight fix and your sysfs
lifetime fix in drm-next.

* tag 'drm-intel-fixes-2013-11-07' of git://people.freedesktop.org/~danvet/drm-intel: (940 commits)
  drm/i915/vlv: use per-pipe backlight controls v2
  drm/i915: make backlight functions take a connector
  drm/i915: move opregion asle request handling to a work queue
  drm/i915/vlv: use PIPE_START_VBLANK interrupts on VLV
  drm/i915: Make intel_dp_is_edp() less specific
  drm/i915: Give names to the VBT child device type bits
  drm/i915/vlv: enable HDA display audio for Valleyview2
  drm/i915/dvo: call ->mode_set callback only when the port is running
  drm/i915: avoid unclaimed registers when capturing the error state
  drm/i915: Enable DP port CRC for the "auto" source on g4x/vlv
  drm/i915: scramble reset support for DP port CRC on vlv
  drm/i915: scramble reset support for DP port CRC on g4x
  drm/i916: add "auto" pipe CRC source
  ...

Conflicts:
	MAINTAINERS
	drivers/gpu/drm/i915/intel_panel.c
	drivers/gpu/drm/nouveau/core/subdev/mc/base.c
	drivers/gpu/drm/radeon/atombios_encoders.c
	drivers/gpu/drm/radeon/radeon_connectors.c

1 files changed, 27 insertions, 4 deletions

diff --git a/kernel/events/ring_buffer.c b/kernel/events/ring_buffer.c
index cd55144..9c2ddfb 100644
--- a/kernel/events/ring_buffer.c
+++ b/kernel/events/ring_buffer.c
@@ -87,10 +87,31 @@ again:
 		goto out;
 
 	/*
-	 * Publish the known good head. Rely on the full barrier implied
-	 * by atomic_dec_and_test() order the rb->head read and this
-	 * write.
+	 * Since the mmap() consumer (userspace) can run on a different CPU:
+	 *
+	 *   kernel				user
+	 *
+	 *   READ ->data_tail			READ ->data_head
+	 *   smp_mb()	(A)			smp_rmb()	(C)
+	 *   WRITE $data			READ $data
+	 *   smp_wmb()	(B)			smp_mb()	(D)
+	 *   STORE ->data_head			WRITE ->data_tail
+	 *
+	 * Where A pairs with D, and B pairs with C.
+	 *
+	 * I don't think A needs to be a full barrier because we won't in fact
+	 * write data until we see the store from userspace. So we simply don't
+	 * issue the data WRITE until we observe it. Be conservative for now.
+	 *
+	 * OTOH, D needs to be a full barrier since it separates the data READ
+	 * from the tail WRITE.
+	 *
+	 * For B a WMB is sufficient since it separates two WRITEs, and for C
+	 * an RMB is sufficient since it separates two READs.
+	 *
+	 * See perf_output_begin().
 	 */
+	smp_wmb();
 	rb->user_page->data_head = head;
 
 	/*
@@ -154,9 +175,11 @@ int perf_output_begin(struct perf_output_handle *handle,
 		 * Userspace could choose to issue a mb() before updating the
 		 * tail pointer. So that all reads will be completed before the
 		 * write is issued.
+		 *
+		 * See perf_output_put_handle().
 		 */
 		tail = ACCESS_ONCE(rb->user_page->data_tail);
-		smp_rmb();
+		smp_mb();
 		offset = head = local_read(&rb->head);
 		head += size;
 		if (unlikely(!perf_output_space(rb, tail, offset, head)))