[PATCH] drm/i915: Emit even number of dwords when emitting LRIs

Arun Siluvery
2014-10-22T18:00:24Z

The number of DWords should be even when doing ring emits as
command sequences require QWord alignment.

v2: user LRI variant that can write multiple regs in one go (Damien).
We can simply insert one NOP at the end instead of one per register write.

Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery@linux.intel.com>
---
drivers/gpu/drm/i915/intel_ringbuffer.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
index 497b836..a8f72e8 100644
--- a/drivers/gpu/drm/i915/intel_ringbuffer.c
+++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
@@ -680,15 +680,16 @@ static int intel_ring_workarounds_emit(struct intel_engine_cs *ring)
if (ret)
return ret;

- ret = intel_ring_begin(ring, w->count * 3);
+ ret = intel_ring_begin(ring, (w->count * 2 + 2));
if (ret)
return ret;

+ intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(w->count));
for (i = 0; i < w->count; i++) {
- intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
intel_ring_emit(ring, w->reg[i].addr);
intel_ring_emit(ring, w->reg[i].value);
}
+ intel_ring_emit(ring, MI_NOOP);

intel_ring_advance(ring);

--
2.1.2