From 60e4c994884ac10954f341db13a4c9c410c4dd0e Mon Sep 17 00:00:00 2001 From: Matt Turner Date: Mon, 15 Apr 2013 14:59:09 -0700 Subject: [PATCH] i965: Implement work-around for CMP with null dest on Haswell. Reviewed-by: Kenneth Graunke --- src/mesa/drivers/dri/i965/brw_eu_emit.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c index 2578bf89cca..704f219f6f7 100644 --- a/src/mesa/drivers/dri/i965/brw_eu_emit.c +++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c @@ -1653,6 +1653,7 @@ void brw_CMP(struct brw_compile *p, struct brw_reg src0, struct brw_reg src1) { + struct intel_context *intel = &p->brw->intel; struct brw_instruction *insn = next_insn(p, BRW_OPCODE_CMP); insn->header.destreg__conditionalmod = conditional; @@ -1672,6 +1673,17 @@ void brw_CMP(struct brw_compile *p, p->current->header.predicate_control = BRW_PREDICATE_NORMAL; p->flag_value = 0xff; } + + /* Item WaCMPInstNullDstForcesThreadSwitch in the Haswell Bspec workarounds + * page says: + * "Any CMP instruction with a null destination must use a {switch}." + */ + if (intel->is_haswell) { + if (dest.file == BRW_ARCHITECTURE_REGISTER_FILE && + dest.nr == BRW_ARF_NULL) { + insn->header.thread_control = BRW_THREAD_SWITCH; + } + } } /* Issue 'wait' instruction for n1, host could program MMIO -- 2.30.2