--- /dev/null
+From 7ee4db50b10ab2d8fdfc4781f26b84041cf568d7 Mon Sep 17 00:00:00 2001
+From: Eric Anholt <eric@anholt.net>
+Date: Wed, 10 Mar 2010 10:38:20 -0800
+Subject: [PATCH] i965: Fix the response len of masked sampler messages for 8-wide dispatch.
+
+The bad response length would hang the GPU with a masked sample in a
+shader using control flow. For 8-wide, the response length is always
+4, and masked slots are just not written to. brw_wm_glsl.c already
+allocates registers in the right locations.
+
+Fixes piglit glsl-fs-bug25902 (fd.o bug #25902).
+(cherry picked from commit f6d210c284751ac50a8d6358de7e75a1ff1e4ac7)
+(cherry picked from commit dc8c0359448cdae7b367552ba58783c04b199778)
+---
+ src/mesa/drivers/dri/i965/brw_eu_emit.c | 18 +++++++++++++++---
+ 1 files changed, 15 insertions(+), 3 deletions(-)
+
+diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c b/src/mesa/drivers/dri/i965/brw_eu_emit.c
+index f69d529..82f2fda 100644
+--- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
++++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
+@@ -1290,7 +1290,7 @@ void brw_SAMPLE(struct brw_compile *p,
+ GLuint simd_mode)
+ {
+ GLboolean need_stall = 0;
+-
++
+ if (writemask == 0) {
+ /*printf("%s: zero writemask??\n", __FUNCTION__); */
+ return;
+@@ -1327,8 +1327,14 @@ void brw_SAMPLE(struct brw_compile *p,
+ /* printf("need stall %x %x\n", newmask , writemask); */
+ }
+ else {
++ GLboolean dispatch_16 = GL_FALSE;
++
+ struct brw_reg m1 = brw_message_reg(msg_reg_nr);
+-
++
++ guess_execution_size(p->current, dest);
++ if (p->current->header.execution_size == BRW_EXECUTE_16)
++ dispatch_16 = GL_TRUE;
++
+ newmask = ~newmask & WRITEMASK_XYZW;
+
+ brw_push_insn_state(p);
+@@ -1343,7 +1349,13 @@ void brw_SAMPLE(struct brw_compile *p,
+
+ src0 = retype(brw_null_reg(), BRW_REGISTER_TYPE_UW);
+ dest = offset(dest, dst_offset);
+- response_length = len * 2;
++
++ /* For 16-wide dispatch, masked channels are skipped in the
++ * response. For 8-wide, masked channels still take up slots,
++ * and are just not written to.
++ */
++ if (dispatch_16)
++ response_length = len * 2;
+ }
+ }
+
+--
+1.6.4.4
+