From: Connor Abbott <connor.w.abb...@intel.com>
It appears that not only math instructions, but also MOV_BYTES or
any instruction that uses Align1 mode cannot be in the middle
of a dependency control sequence or the GPU will hang (at least on my
BDW). This fixes GPU hangs in some fp64 tests.
Reviewed-by: Iago Toral Quiroga <ito...@igalia.com>
---
src/mesa/drivers/dri/i965/brw_vec4.cpp | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp
b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index 3bcd5cb..bc0a33b 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -838,6 +838,17 @@ vec4_visitor::is_dep_ctrl_unsafe(const vec4_instruction
*inst)
}
/*
+ * Instructions that use Align1 mode cause the GPU to hang when inserted
+ * between a NoDDClr and NoDDChk in Align16 mode. Discovered empirically.
+ */
+
+ if (inst->opcode == VEC4_OPCODE_PACK_BYTES ||
+ inst->opcode == VEC4_OPCODE_MOV_BYTES ||
+ inst->is_math())
+ return true;
+
+
+ /*
* mlen:
* In the presence of send messages, totally interrupt dependency
* control. They're long enough that the chance of dependency
@@ -851,12 +862,8 @@ vec4_visitor::is_dep_ctrl_unsafe(const vec4_instruction
*inst)
* enable of the last instruction, the optimization must be avoided. This is
* to avoid instructions being shot down the pipeline when no writes are
* required.
- *
- * math:
- * Dependency control does not work well over math instructions.
- * NB: Discovered empirically
*/
- return (inst->mlen || inst->predicate || inst->is_math());
+ return (inst->mlen || inst->predicate);
}
/**
--
1.9.1
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