From 424a6052dfe76d9d6fd3679d79dd7d4d093771e3 Mon Sep 17 00:00:00 2001 From: Kenneth Graunke Date: Mon, 8 Oct 2018 14:54:00 -0700 Subject: [PATCH] intel: Use a URB start offset of 0 for disabled stages. There are some cases where the VS is the only stage enabled, it uses the entire URB, and the URB is large enough that placing later stages after the VS exceeds the number of bits for "URB Starting Address". For example, on Icelake GT2, "varying-packing-simple mat2x4 array" from Piglit is getting a starting offset of 128 for the GS/HS/DS. But the field is only large enough to hold an offset of 127. i965 doesn't hit any genxml assertions because it's still using the old OUT_BATCH mechanism. 128 << GEN7_URB_STARTING_ADDRESS_SHIFT (57) == 0, with the extra bit falling off the end. So we place the disabled stage at the beginning of the URB (overlapping with push constants). This is likely okay since it's a zero size region (0 entries). It seems like the Vulkan driver might hit this assertion, however, and the situation seems harmless. To work around this, always place disabled stages at the start of the URB, so the last enabled stage can fill the remaining space without overflowing the field. Reviewed-by: Jordan Justen --- src/intel/common/gen_urb_config.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/intel/common/gen_urb_config.c b/src/intel/common/gen_urb_config.c index 0b632149cd9..1440dd713e9 100644 --- a/src/intel/common/gen_urb_config.c +++ b/src/intel/common/gen_urb_config.c @@ -195,8 +195,14 @@ gen_get_urb_config(const struct gen_device_info *devinfo, } /* Lay out the URB in pipeline order: push constants, VS, HS, DS, GS. */ - start[0] = push_constant_chunks; - for (int i = MESA_SHADER_TESS_CTRL; i <= MESA_SHADER_GEOMETRY; i++) { - start[i] = start[i - 1] + chunks[i - 1]; + int next = push_constant_chunks; + for (int i = MESA_SHADER_VERTEX; i <= MESA_SHADER_GEOMETRY; i++) { + if (entries[i]) { + start[i] = next; + next += chunks[i]; + } else { + /* Just put disabled stages at the beginning. */ + start[i] = 0; + } } } -- 2.30.2