Potential fix for doom3 lockups. Seems that there is a conflict

between the vertex cache, the vertex shader and the clipping stages,
all of which are competitors for URB entries assigned to the VS unit.
This change reduces the maximum number of clip and VS threads by
enough to ensure that they cannot consume all the available URB
entries, and then reduces the number somewhat more up to an arbitary
amount I discovered by trial and error.  Unfortunately trial and error
solutions don't inspire total confidence...

diff --git a/src/mesa/drivers/dri/i965/brw_clip_state.c b/src/mesa/drivers/dri/i965/brw_clip_state.c
index cb98285..1e6d6fa 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_clip_state.c
+++ b/src/mesa/drivers/dri/i965/brw_clip_state.c
@@ -55,10 +55,7 @@ static void upload_clip_unit( struct brw_context *brw )
    /* BRW_NEW_URB_FENCE */
    clip.thread4.nr_urb_entries = brw->urb.nr_clip_entries; 
    clip.thread4.urb_entry_allocation_size = brw->urb.vsize - 1;
-   clip.thread4.max_threads = MIN2(brw->urb.nr_clip_entries, 16) - 1;
-
-   if (INTEL_DEBUG & DEBUG_SINGLE_THREAD)
-      clip.thread4.max_threads = 0;
+   clip.thread4.max_threads = 0; /* Hmm, maybe the max is 1 or 2 threads */
 
    if (INTEL_DEBUG & DEBUG_STATS)
       clip.thread4.stats_enable = 1; 

diff --git a/src/mesa/drivers/dri/i965/brw_urb.c b/src/mesa/drivers/dri/i965/brw_urb.c
index 40af0bf..b429304 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_urb.c
+++ b/src/mesa/drivers/dri/i965/brw_urb.c
@@ -53,7 +53,7 @@ static const struct {
    GLuint min_entry_size;
    GLuint max_entry_size;
 } limits[CS+1] = {
-   { 8, 16, 1, 5 },                    /* vs */
+   { 8, 24, 1, 5 },                    /* vs */
    { 4, 8,  1, 5 },                    /* gs */
    { 6, 12, 1, 5 },                    /* clp */
    { 1, 8,  1, 12 },                   /* sf */

diff --git a/src/mesa/drivers/dri/i965/brw_vs_state.c b/src/mesa/drivers/dri/i965/brw_vs_state.c
index 70de0e8..c225bf8 100644 (file)
--- a/src/mesa/drivers/dri/i965/brw_vs_state.c
+++ b/src/mesa/drivers/dri/i965/brw_vs_state.c
@@ -53,7 +53,11 @@ static void upload_vs_unit( struct brw_context *brw )
    /* BRW_NEW_URB_FENCE  */
    vs.thread4.nr_urb_entries = brw->urb.nr_vs_entries; 
    vs.thread4.urb_entry_allocation_size = brw->urb.vsize - 1;
-   vs.thread4.max_threads = MIN2(brw->urb.nr_vs_entries, 16) - 1;
+   vs.thread4.max_threads = MIN2(
+      MAX2(0, (brw->urb.nr_vs_entries - 6) / 2 - 1), 
+      15);
+
+
 
    if (INTEL_DEBUG & DEBUG_SINGLE_THREAD)
       vs.thread4.max_threads = 0;