i965/vs: Fix unit mismatch in scratch base_offset parameter.

move_grf_array_access_to_scratch() calculates scratch buffer offsets in
bytes.  However, emit_scratch_read/write() expects the base_offset
parameter to be measured in OWords.

As a result, a shader using a scratch read/write offset greater than
zero (in practice, a shader containing more than one variable in
scratch) would use too large an offset, frequently exceeding the
available scratch space.

This patch corrects the mismatch by removing spurious conversion from
OWords to bytes in move_grf_array_access_to_scratch().

This is based on a patch by Paul Berry.

NOTE: This is a candidate for stable release branches.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Eric Anholt <eric@anholt.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_vs.h b/src/mesa/drivers/dri/i965/brw_vs.h
index e04247f..adeff7f 100644
--- a/src/mesa/drivers/dri/i965/brw_vs.h
+++ b/src/mesa/drivers/dri/i965/brw_vs.h
@@ -93,7 +93,7 @@ struct brw_vs_compile {
    GLuint nr_inputs;
 
    GLuint first_output;
-   GLuint last_scratch;
+   GLuint last_scratch; /**< measured in 32-byte (register size) units */
 
    GLuint first_tmp;
    GLuint last_tmp;