drm/i915: Avoid snooping with userptr where not supported
commit e5756c10d841ddb448293c849392f3d6b809561f
Author: Imre Deak <imre.deak@intel.com>
Date: Fri Aug 14 18:43:30 2015 +0300
drm/i915/bxt: don't allow cached GEM mappings on A stepping
Added an exception of disallowing snooping for Broxton A
stepping hardware but userptr was still enabling it regardless.
Move the check to HAS_SNOOP now that it is used from multiple
call sites and use it.
v2: Userptr cannot be supported when it cannot be coherent and
generalize the code better. (Chris Wilson)
v3: Make has_snoop true only when !has_llc. (Chris Wilson)
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Imre Deak <imre.deak@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1456920631-34302-1-git-send-email-tvrtko.ursulin@linux.intel.com
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index 36c0cf1..4aa3db6 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -853,6 +853,10 @@
else if (INTEL_INFO(dev)->gen >= 9)
gen9_sseu_info_init(dev);
+ /* Snooping is broken on BXT A stepping. */
+ info->has_snoop = !info->has_llc;
+ info->has_snoop &= !IS_BXT_REVID(dev, 0, BXT_REVID_A1);
+
DRM_DEBUG_DRIVER("slice total: %u\n", info->slice_total);
DRM_DEBUG_DRIVER("subslice total: %u\n", info->subslice_total);
DRM_DEBUG_DRIVER("subslice per slice: %u\n", info->subslice_per_slice);