4 files changed, 10 insertions, 2 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 90805e45ad7..688f431f5c6 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -1558,6 +1558,8 @@ fs_generator::generate_code(const cfg_t *cfg, int dispatch_width)
       brw_set_default_acc_write_control(p, inst->writes_accumulator);
       brw_set_default_exec_size(p, cvt(inst->exec_size) - 1);
 
+      assert(inst->mlen <= BRW_MAX_MSG_LENGTH);
+
       switch (inst->exec_size) {
       case 1:
       case 2:
diff --git a/src/mesa/drivers/dri/i965/brw_inst.h b/src/mesa/drivers/dri/i965/brw_inst.h
index 46eff1dd381..c5132ba15ed 100644
--- a/src/mesa/drivers/dri/i965/brw_inst.h
+++ b/src/mesa/drivers/dri/i965/brw_inst.h
@@ -39,6 +39,9 @@
 extern "C" {
 #endif
 
+/** Maximum SEND message length */
+#define BRW_MAX_MSG_LENGTH 15
+
 /* brw_context.h has a forward declaration of brw_inst, so name the struct. */
 typedef struct brw_inst {
    uint64_t data[2];
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
index 195033358fb..f11d3c3615d 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
@@ -1134,6 +1134,8 @@ vec4_generator::generate_code(const cfg_t *cfg)
       brw_set_default_mask_control(p, inst->force_writemask_all);
       brw_set_default_acc_write_control(p, inst->writes_accumulator);
 
+      assert(inst->mlen <= BRW_MAX_MSG_LENGTH);
+
       unsigned pre_emit_nr_insn = p->nr_insn;
 
       if (dst.width == BRW_WIDTH_4) {
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index 04657704405..e210bb4ad2c 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -3318,9 +3318,10 @@ vec4_visitor::emit_vertex()
                        prog_data->vue_map.slot_to_varying[slot]);
 
          /* If this was max_usable_mrf, we can't fit anything more into this
-          * URB WRITE.
+          * URB WRITE. Same thing if we reached the maximum length available.
           */
-         if (mrf > max_usable_mrf) {
+         if (mrf > max_usable_mrf ||
+             align_interleaved_urb_mlen(devinfo, mrf - base_mrf + 1) > BRW_MAX_MSG_LENGTH) {
             slot++;
             break;
          }