The (2<<6) virtual memory space selector harks back to gen3 and is
mandatory given our use of GTT space for batchbuffers. On gen4+, use of
the GTT became mandatory and bit6 marked reserved. However the code must
now explicitly set (1<<7), which conveniently is also (2<<6).

To clarify the meaning for future readers, replace the open coded (2<<6)
with MI_BATCH_GTT.

Signed-off-by: Chris Wilson <[email protected]>
---
 drivers/gpu/drm/i915/i915_reg.h         |    1 +
 drivers/gpu/drm/i915/intel_ringbuffer.c |    5 +++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index b5f937a..f617437 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -231,6 +231,7 @@
 #define   MI_BATCH_NON_SECURE  (1)
 #define   MI_BATCH_NON_SECURE_I965 (1<<8)
 #define MI_BATCH_BUFFER_START  MI_INSTR(0x31, 0)
+#define   MI_BATCH_GTT             (2<<6) /* aliased with (1<<7) on gen4 */
 #define MI_SEMAPHORE_MBOX      MI_INSTR(0x16, 1) /* gen6+ */
 #define  MI_SEMAPHORE_GLOBAL_GTT    (1<<22)
 #define  MI_SEMAPHORE_UPDATE       (1<<21)
diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c 
b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 90eddd3..7270d06 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -817,7 +817,8 @@ i965_dispatch_execbuffer(struct intel_ring_buffer *ring, 
u32 offset, u32 length)
                return ret;
 
        intel_ring_emit(ring,
-                       MI_BATCH_BUFFER_START | (2 << 6) |
+                       MI_BATCH_BUFFER_START |
+                       MI_BATCH_GTT |
                        MI_BATCH_NON_SECURE_I965);
        intel_ring_emit(ring, offset);
        intel_ring_advance(ring);
@@ -854,7 +855,7 @@ i915_dispatch_execbuffer(struct intel_ring_buffer *ring,
        if (ret)
                return ret;
 
-       intel_ring_emit(ring, MI_BATCH_BUFFER_START | (2 << 6));
+       intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_GTT);
        intel_ring_emit(ring, offset | MI_BATCH_NON_SECURE);
        intel_ring_advance(ring);
 
-- 
1.7.10

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