[ 3.5.y.z extended stable ] Patch "drm/i915: Invalidate TLBs for the rings after a reset" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    drm/i915: Invalidate TLBs for the rings after a reset

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From d1b3c4c2b5677f2768e85310dbead411a539423f Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris at chris-wilson.co.uk>
Date: Tue, 6 Aug 2013 19:01:14 +0100
Subject: [PATCH] drm/i915: Invalidate TLBs for the rings after a reset

commit 884020bf3d2a3787a1cc6df902e98e0eec60330b upstream.

After any "soft gfx reset" we must manually invalidate the TLBs
associated with each ring. Empirically, it seems that a
suspend/resume or D3-D0 cycle count as a "soft reset". The symptom is
that the hardware would fail to note the new address for its status
page, and so it would continue to write the shadow registers and
breadcrumbs into the old physical address (now used by something
completely different, scary). Whereas the driver would read the new
status page and never see any progress, it would appear that the GPU
hung immediately upon resume.

Based on a patch by naresh kumar kachhi <naresh.kumar.kacchi at intel.com>

Reported-by: Thiago Macieira <thiago at kde.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64725
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Tested-by: Thiago Macieira <thiago at kde.org>
Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/gpu/drm/i915/i915_reg.h         |  2 ++
 drivers/gpu/drm/i915/intel_ringbuffer.c | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 26b8bba..70bfc0f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -572,6 +572,8 @@
 					will not assert AGPBUSY# and will only
 					be delivered when out of C3. */
 #define   INSTPM_FORCE_ORDERING				(1<<7) /* GEN6+ */
+#define   INSTPM_TLB_INVALIDATE	(1<<9)
+#define   INSTPM_SYNC_FLUSH	(1<<5)
 #define ACTHD	        0x020c8
 #define FW_BLC		0x020d8
 #define FW_BLC2		0x020dc
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 78486c7..7e9d3db 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -773,6 +773,18 @@ void intel_ring_setup_status_page(struct intel_ring_buffer *ring)

 	I915_WRITE(mmio, (u32)ring->status_page.gfx_addr);
 	POSTING_READ(mmio);
+
+	/* Flush the TLB for this page */
+	if (INTEL_INFO(dev)->gen >= 6) {
+		u32 reg = RING_INSTPM(ring->mmio_base);
+		I915_WRITE(reg,
+			   _MASKED_BIT_ENABLE(INSTPM_TLB_INVALIDATE |
+					      INSTPM_SYNC_FLUSH));
+		if (wait_for((I915_READ(reg) & INSTPM_SYNC_FLUSH) == 0,
+			     1000))
+			DRM_ERROR("%s: wait for SyncFlush to complete for TLB invalidation timed out\n",
+				  ring->name);
+	}
 }

 static int
--
1.8.3.2