[Mesa-dev] [PATCH 3/7] i965: Use 64-bit writes for timestamp queries.

Kenneth Graunke kenneth at whitecape.org
Tue Aug 7 16:05:29 PDT 2012


The hardware seems to use the length of the PIPE_CONTROL command to
indicate whether the write is 64-bits or 32-bits.  Which makes sense
for immediate writes.

Daniel discovered this by writing a pattern into the query object bo
and noticing that the high 32-bits were left intact, even on those
pipe control writes that seemingly worked.

Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/mesa/drivers/dri/i965/brw_queryobj.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_queryobj.c b/src/mesa/drivers/dri/i965/brw_queryobj.c
index 229aeb7..afa3091 100644
--- a/src/mesa/drivers/dri/i965/brw_queryobj.c
+++ b/src/mesa/drivers/dri/i965/brw_queryobj.c
@@ -49,14 +49,15 @@ static void
 write_timestamp(struct intel_context *intel, drm_intel_bo *query_bo, int idx)
 {
    if (intel->gen >= 6) {
-      BEGIN_BATCH(4);
-      OUT_BATCH(_3DSTATE_PIPE_CONTROL | (4 - 2));
+      BEGIN_BATCH(5);
+      OUT_BATCH(_3DSTATE_PIPE_CONTROL | (5 - 2));
       OUT_BATCH(PIPE_CONTROL_WRITE_TIMESTAMP);
       OUT_RELOC(query_bo,
                 I915_GEM_DOMAIN_INSTRUCTION, I915_GEM_DOMAIN_INSTRUCTION,
                 PIPE_CONTROL_GLOBAL_GTT_WRITE |
                 idx * sizeof(uint64_t));
       OUT_BATCH(0);
+      OUT_BATCH(0);
       ADVANCE_BATCH();
    } else {
       BEGIN_BATCH(4);
-- 
1.7.11.4



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