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

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@intel.com>

Reported-by: Thiago Macieira <thiago@kde.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64725
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Thiago Macieira <thiago@kde.org>
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

2 files changed, 14 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6f514297c483..53cddd985406 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -752,6 +752,8 @@
                                         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 664118d8c1d6..079ef0129e74 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -968,6 +968,18 @@ 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