From: Alex Deucher <alexander.deucher@xxxxxxx>
When submitting a CONST_IB, emit a SWITCH_BUFFER
packet before the CONST_IB. This isn't strictly necessary
(the driver will work fine without it), but is good practice
and allows for more flexible DE/CE sychronization options
in the future. Current userspace drivers do not take
advantage of the CE yet.
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/gpu/drm/radeon/si.c | 6 ++++++
drivers/gpu/drm/radeon/sid.h | 1 +
2 files changed, 7 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index 53e313b..191a3cd 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -1778,6 +1778,12 @@ void si_ring_ib_execute(struct radeon_device *rdev, struct radeon_ib *ib)
else
header = PACKET3(PACKET3_INDIRECT_BUFFER, 2);
+ if (ib->is_const_ib) {
+ /* set switch buffer packet before const IB */
+ radeon_ring_write(ring, PACKET3(PACKET3_SWITCH_BUFFER, 0));
+ radeon_ring_write(ring, 0);
+ }
+
radeon_ring_write(ring, header);
radeon_ring_write(ring,
#ifdef __BIG_ENDIAN
diff --git a/drivers/gpu/drm/radeon/sid.h b/drivers/gpu/drm/radeon/sid.h
index db40679..7869089 100644
--- a/drivers/gpu/drm/radeon/sid.h
+++ b/drivers/gpu/drm/radeon/sid.h
@@ -901,5 +901,6 @@
#define PACKET3_WAIT_ON_DE_COUNTER_DIFF 0x88
#define PACKET3_SET_CE_DE_COUNTERS 0x89
#define PACKET3_WAIT_ON_AVAIL_BUFFER 0x8A
+#define PACKET3_SWITCH_BUFFER 0x8B
#endif
--
1.7.7.5
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