i965g: add lots of error checks and early returns

Any allocation that may fail should be checked, and propogate the
error upwards.  At the highest level we will flush batch and retry.

This is an alternate strategy to what the original DRI driver did of
attempting to flush batch from the lowest levels (eg inside
BEGIN_BATCH).  The trouble with that strategy was that flushes could
occur at unexpected times, and additionally there was a need for a
wierd notification mechanism to propogate the 'lost context' state
back up to higher levels.

Propogating the errors directly gives us a lot of flexibility how to
deal with these states, at the expense of a lot more checking in the
code.

Will add some sanity checks later to make sure that out-of-memory
conditions are properly escalated and not lost halfway up the stack.

1 files changed, 34 insertions, 22 deletions

diff --git a/src/gallium/drivers/i965/brw_vs.c b/src/gallium/drivers/i965/brw_vs.c
index 26a28114d98..966940ceacb 100644
--- a/src/gallium/drivers/i965/brw_vs.c
+++ b/src/gallium/drivers/i965/brw_vs.c
@@ -39,10 +39,12 @@
 
 
 
-static void do_vs_prog( struct brw_context *brw, 
-			struct brw_vertex_shader *vp,
-			struct brw_vs_prog_key *key )
+static enum pipe_error do_vs_prog( struct brw_context *brw, 
+                                   struct brw_vertex_shader *vp,
+                                   struct brw_vs_prog_key *key,
+                                   struct brw_winsys_buffer **bo_out)
 {
+   enum pipe_error ret;
    GLuint program_size;
    const GLuint *program;
    struct brw_vs_compile c;
@@ -66,22 +68,29 @@ static void do_vs_prog( struct brw_context *brw,
 
    /* get the program
     */
-   program = brw_get_program(&c.func, &program_size);
-
-   brw->sws->bo_unreference(brw->vs.prog_bo);
-   brw->vs.prog_bo = brw_upload_cache( &brw->cache, BRW_VS_PROG,
-				       &c.key, sizeof(c.key),
-				       NULL, 0,
-				       program, program_size,
-				       &c.prog_data,
-				       &brw->vs.prog_data );
+   ret = brw_get_program(&c.func, &program, &program_size);
+   if (ret)
+      return ret;
+
+   ret = brw_upload_cache( &brw->cache, BRW_VS_PROG,
+                           &c.key, sizeof(c.key),
+                           NULL, 0,
+                           program, program_size,
+                           &c.prog_data,
+                           &brw->vs.prog_data,
+                           bo_out);
+   if (ret)
+      return ret;
+
+   return PIPE_OK;
 }
 
 
-static int brw_upload_vs_prog(struct brw_context *brw)
+static enum pipe_error brw_upload_vs_prog(struct brw_context *brw)
 {
    struct brw_vs_prog_key key;
    struct brw_vertex_shader *vp = brw->curr.vertex_shader;
+   enum pipe_error ret;
 
    memset(&key, 0, sizeof(key));
 
@@ -95,15 +104,18 @@ static int brw_upload_vs_prog(struct brw_context *brw)
 
    /* Make an early check for the key.
     */
-   brw->sws->bo_unreference(brw->vs.prog_bo);
-   brw->vs.prog_bo = brw_search_cache(&brw->cache, BRW_VS_PROG,
-				      &key, sizeof(key),
-				      NULL, 0,
-				      &brw->vs.prog_data);
-   if (brw->vs.prog_bo == NULL)
-      do_vs_prog(brw, vp, &key);
-
-   return 0;
+   if (brw_search_cache(&brw->cache, BRW_VS_PROG,
+                        &key, sizeof(key),
+                        NULL, 0,
+                        &brw->vs.prog_data,
+                        &brw->vs.prog_bo))
+      return PIPE_OK;
+
+   ret = do_vs_prog(brw, vp, &key, &brw->vs.prog_bo);
+   if (ret)
+      return ret;
+
+   return PIPE_OK;
 }