Mesa (master): r300/compiler: Fix scheduler bug causing texture corruption
Tom Stellard
tstellar at kemper.freedesktop.org
Fri Oct 28 00:57:52 UTC 2011
Module: Mesa
Branch: master
Commit: 17a1c0cb0d9e04607c1726d04ef23485979dfc98
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=17a1c0cb0d9e04607c1726d04ef23485979dfc98
Author: Tom Stellard <tstellar at gmail.com>
Date: Sat Oct 22 18:30:46 2011 -0700
r300/compiler: Fix scheduler bug causing texture corruption
We weren't setting TEX_SEM_WAIT on instructions that read the value of a
TEX instruction and also wrote the same register as the TEX instruction.
This is the sequence we were miscompiling:
1: TEX temp[0], input[2].xy__, 2D[0]
...
16: src0.xyz = temp[22], src1.xyz = temp[0], src2.xyz = temp[19]
MAD temp[0].xyz, src0.xxx, src1.xyz, src2.xxx
https://bugs.freedesktop.org/show_bug.cgi?id=42090
---
.../drivers/r300/compiler/radeon_pair_schedule.c | 41 +++++++++++++++++---
1 files changed, 35 insertions(+), 6 deletions(-)
diff --git a/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c b/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c
index b3b0f6f..fa2e80f 100644
--- a/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c
+++ b/src/gallium/drivers/r300/compiler/radeon_pair_schedule.c
@@ -132,6 +132,9 @@ struct remap_reg {
struct schedule_state {
struct radeon_compiler * C;
struct schedule_instruction * Current;
+ /** Array of the previous writers of Current's destination register
+ * indexed by channel. */
+ struct schedule_instruction * PrevWriter[4];
struct register_state Temporary[RC_REGISTER_MAX_INDEX];
@@ -1137,6 +1140,19 @@ static void emit_one_alu(struct schedule_state *s, struct rc_instruction * befor
presub_nop(before->Prev);
}
+static void add_tex_reader(
+ struct schedule_state * s,
+ struct schedule_instruction * writer,
+ struct schedule_instruction * reader)
+{
+ if (!writer || writer->Instruction->Type != RC_INSTRUCTION_NORMAL) {
+ /*Not a TEX instructions */
+ return;
+ }
+ reader->TexReadCount++;
+ rc_list_add(&writer->TexReaders, rc_list(&s->C->Pool, reader));
+}
+
static void scan_read(void * data, struct rc_instruction * inst,
rc_register_file file, unsigned int index, unsigned int chan)
{
@@ -1150,7 +1166,22 @@ static void scan_read(void * data, struct rc_instruction * inst,
if (*v && (*v)->Writer == s->Current) {
/* The instruction reads and writes to a register component.
* In this case, we only want to increment dependencies by one.
+ * Why?
+ * Because each instruction depends on the writers of its source
+ * registers _and_ the most recent writer of its destination
+ * register. In this case, the current instruction (s->Current)
+ * has a dependency that both writes to one of its source
+ * registers and was the most recent writer to its destination
+ * register. We have already marked this dependency in
+ * scan_write(), so we don't need to do it again.
+ */
+
+ /* We need to make sure we are adding s->Current to the
+ * previous writer's list of TexReaders, if the previous writer
+ * was a TEX instruction.
*/
+ add_tex_reader(s, s->PrevWriter[chan], s->Current);
+
return;
}
@@ -1171,12 +1202,7 @@ static void scan_read(void * data, struct rc_instruction * inst,
/* Only update the current instruction's dependencies if the
* register it reads from has been written to in this block. */
if ((*v)->Writer) {
- if ((*v)->Writer->Instruction->Type ==
- RC_INSTRUCTION_NORMAL) {
- s->Current->TexReadCount++;
- rc_list_add(&((*v)->Writer->TexReaders),
- rc_list(&s->C->Pool, s->Current));
- }
+ add_tex_reader(s, (*v)->Writer, s->Current);
s->Current->NumDependencies++;
}
}
@@ -1209,6 +1235,9 @@ static void scan_write(void * data, struct rc_instruction * inst,
if (*pv) {
(*pv)->Next = newv;
s->Current->NumDependencies++;
+ /* Keep track of the previous writer to s->Current's destination
+ * register */
+ s->PrevWriter[chan] = (*pv)->Writer;
}
*pv = newv;
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