drm/i915: Added write-enable pte bit supportt
This adds support for a write-enable bit in the entry of GTT.
This is handled via a read-only flag in the GEM buffer object which
is then used to see how to set the bit when writing the GTT entries.
Currently by default the Batch buffer & Ring buffers are marked as read only.
v2: Moved the pte override code for read-only bit to 'byt_pte_encode'. (Chris)
Fixed the issue of leaving 'gt_old_ro' as unused. (Chris)
v3: Removed the 'gt_old_ro' field, now setting RO bit only for Ring Buffers(Daniel).
v4: Added a new 'flags' parameter to all the pte(gen6) encode & insert_entries functions,
in lieu of overloading the cache_level enum (Daniel).
v5: Removed the superfluous VLV check & changed the definition location of PTE_READ_ONLY flag (Imre)
Reviewed-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Akash Goel <akash.goel@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 0eaaaec..b96edaf 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -1397,6 +1397,9 @@
if (obj == NULL)
return -ENOMEM;
+ /* mark ring buffers as read-only from GPU side by default */
+ obj->gt_ro = 1;
+
ret = i915_gem_obj_ggtt_pin(obj, PAGE_SIZE, PIN_MAPPABLE);
if (ret)
goto err_unref;