diff --git a/src/mesa/drivers/dri/i965/brw_vec4_gs.c b/src/mesa/drivers/dri/i965/brw_vec4_gs.c index 018b0b67461..c40112b0f1f 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_gs.c +++ b/src/mesa/drivers/dri/i965/brw_vec4_gs.c @@ -194,6 +194,12 @@ do_gs_prog(struct brw_context *brw, c.prog_data.output_vertex_size_hwords * 32 * gp->program.VerticesOut; output_size_bytes += 32 * c.prog_data.control_data_header_size_hwords; + /* Broadwell stores "Vertex Count" as a full 8 DWord (32 byte) URB output, + * which comes before the control header. + */ + if (brw->gen >= 8) + output_size_bytes += 32; + assert(output_size_bytes >= 1); if (output_size_bytes > GEN7_MAX_GS_URB_ENTRY_SIZE_BYTES) return false; diff --git a/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp index f33c80dae3d..f0351eaa32a 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_gs_visitor.cpp @@ -267,6 +267,13 @@ vec4_gs_visitor::emit_urb_write_opcode(bool complete) vec4_instruction *inst = emit(GS_OPCODE_URB_WRITE); inst->offset = c->prog_data.control_data_header_size_hwords; + + /* We need to increment Global Offset by 1 to make room for Broadwell's + * extra "Vertex Count" payload at the beginning of the URB entry. + */ + if (brw->gen >= 8) + inst->offset++; + inst->urb_write_flags = BRW_URB_WRITE_PER_SLOT_OFFSET; return inst; }