[Intel-gfx] [PATCH] drm/i915: Init PPGTT before context enable

[David Woodhouse]

Commit 82460d972 ("drm/i915: Rework ppgtt init to no require an aliasing
ppgtt") introduced a regression on Broadwell, triggering the following
IOMMU fault at startup:

  vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=io+mem:owns=io+mem
  dmar: DRHD: handling fault status reg 2
  dmar: DMAR:[DMA Write] Request device [00:02.0] fault addr 880000
  DMAR:[fault reason 23] Unknown
  fbcon: inteldrmfb (fb0) is primary device

Signed-off-by: David Woodhouse <David.Woodhouse at intel.com>
Cc: stable at vger.kernel.org
---
[17:01] <danvet> can you pls submit this as a patch to intel-gfx?
[17:01] <danvet> with the comment above context_enable binned, since that's outdated now anyway

 drivers/gpu/drm/i915/i915_gem.c | 19 ++++++-------------
 1 file changed, 6 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index c11603b..b02a3f3 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -4884,25 +4884,18 @@ i915_gem_init_hw(struct drm_device *dev)
 	for (i = 0; i < NUM_L3_SLICES(dev); i++)
 		i915_gem_l3_remap(&dev_priv->ring[RCS], i);
 
-	/*
-	 * XXX: Contexts should only be initialized once. Doing a switch to the
-	 * default context switch however is something we'd like to do after
-	 * reset or thaw (the latter may not actually be necessary for HW, but
-	 * goes with our code better). Context switching requires rings (for
-	 * the do_switch), but before enabling PPGTT. So don't move this.
-	 */
-	ret = i915_gem_context_enable(dev_priv);
+	ret = i915_ppgtt_init_hw(dev);
 	if (ret && ret != -EIO) {
-		DRM_ERROR("Context enable failed %d\n", ret);
+		DRM_ERROR("PPGTT enable failed %d\n", ret);
 		i915_gem_cleanup_ringbuffer(dev);
-
-		return ret;
 	}
 
-	ret = i915_ppgtt_init_hw(dev);
+	ret = i915_gem_context_enable(dev_priv);
 	if (ret && ret != -EIO) {
-		DRM_ERROR("PPGTT enable failed %d\n", ret);
+		DRM_ERROR("Context enable failed %d\n", ret);
 		i915_gem_cleanup_ringbuffer(dev);
+
+		return ret;
 	}
 
 	return ret;
-- 
2.1.0




-- 
David Woodhouse                            Open Source Technology Centre
David.Woodhouse at intel.com                              Intel Corporation
	
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 5745 bytes
Desc: not available
URL: <http://lists.freedesktop.org/archives/intel-gfx/attachments/20150120/bc164897/attachment.bin>