From e97b968aeb405384d7642c040b4b86d18eb104da Mon Sep 17 00:00:00 2001 From: Lionel Landwerlin Date: Tue, 27 Aug 2024 14:23:19 +0300 Subject: [PATCH] brw: add a comment what Gfx12.5 URB fences Signed-off-by: Lionel Landwerlin Reviewed-by: Rohan Garg Part-of: --- src/intel/compiler/brw_eu_emit.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/intel/compiler/brw_eu_emit.c b/src/intel/compiler/brw_eu_emit.c index bbdfcacc258..be470ce4a76 100644 --- a/src/intel/compiler/brw_eu_emit.c +++ b/src/intel/compiler/brw_eu_emit.c @@ -1817,6 +1817,10 @@ gfx12_set_memory_fence_message(struct brw_codegen *p, brw_inst_set_sfid(p->devinfo, insn, sfid); + /* On Gfx12.5 URB is not listed as port usable for fences with the LSC (see + * BSpec 53578 for Gfx12.5, BSpec 57330 for Gfx20), so we completely ignore + * the descriptor value and rebuild a legacy URB fence descriptor. + */ if (sfid == BRW_SFID_URB && p->devinfo->ver < 20) { brw_set_desc(p, insn, brw_urb_fence_desc(p->devinfo) | brw_message_desc(p->devinfo, mlen, rlen, true));