Programming null constants with gather constant tables seems to
be unsupported and results in a GPU lockup even with the prescribed
GPU workarounds in the bspec. Found out by trial and error that
disabling HW gather constant when the constant state for a stage
needs to be nullified is the only way to go around the issue.
Signed-off-by: Abdiel Janulgue <abdiel.janul...@linux.intel.com>
---
src/mesa/drivers/dri/i965/gen7_disable.c | 4 ++++
src/mesa/drivers/dri/i965/gen7_vs_state.c | 11 +++++++++++
2 files changed, 15 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/gen7_disable.c
b/src/mesa/drivers/dri/i965/gen7_disable.c
index 2c43cd7..ba7fbf8 100644
--- a/src/mesa/drivers/dri/i965/gen7_disable.c
+++ b/src/mesa/drivers/dri/i965/gen7_disable.c
@@ -29,6 +29,8 @@
static void
disable_stages(struct brw_context *brw)
{
+ gen7_toggle_gather_constants(brw, false);
+
/* Disable the HS Unit */
BEGIN_BATCH(7);
OUT_BATCH(_3DSTATE_CONSTANT_HS << 16 | (7 - 2));
@@ -87,6 +89,8 @@ disable_stages(struct brw_context *brw)
OUT_BATCH(_3DSTATE_BINDING_TABLE_POINTERS_DS << 16 | (2 - 2));
OUT_BATCH(0);
ADVANCE_BATCH();
+
+ gen7_toggle_gather_constants(brw, true);
}
const struct brw_tracked_state gen7_disable_stages = {
diff --git a/src/mesa/drivers/dri/i965/gen7_vs_state.c
b/src/mesa/drivers/dri/i965/gen7_vs_state.c
index adfaa59..f5e77ed 100644
--- a/src/mesa/drivers/dri/i965/gen7_vs_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_vs_state.c
@@ -85,6 +85,13 @@ gen7_upload_constant_state(struct brw_context *brw,
int const_loc = use_gather ? 16 : 0;
int dwords = brw->gen >= 8 ? 11 : 7;
+ /* Disable gather constants when zeroing constant states */
+ bool gather_switched_off = false;
+ if (use_gather && !active) {
+ gen7_toggle_gather_constants(brw, false);
+ gather_switched_off = true;
+ }
+
struct brw_stage_prog_data *prog_data = stage_state->prog_data;
if (prog_data && use_gather && active) {
gen7_submit_gather_table(brw, stage_state, prog_data, gather_opcode);
@@ -115,6 +122,10 @@ gen7_upload_constant_state(struct brw_context *brw,
ADVANCE_BATCH();
+ /* Re-enable gather again if required */
+ if (gather_switched_off)
+ gen7_toggle_gather_constants(brw, true);
+
/* On SKL+ the new constants don't take effect until the next corresponding
* 3DSTATE_BINDING_TABLE_POINTER_* command is parsed so we need to ensure
* that is sent
--
1.9.1
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