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, 11 insertions, 7 deletions

diff --git a/src/gallium/drivers/i965/brw_curbe.c b/src/gallium/drivers/i965/brw_curbe.c
index 1e2e232204e..ca7774a7cc2 100644
--- a/src/gallium/drivers/i965/brw_curbe.c
+++ b/src/gallium/drivers/i965/brw_curbe.c
@@ -160,10 +160,11 @@ static GLfloat fixed_plane[6][4] = {
  * cache mechanism, but maybe would benefit from a comparison against
  * the current uploaded set of constants.
  */
-static int prepare_curbe_buffer(struct brw_context *brw)
+static enum pipe_error prepare_curbe_buffer(struct brw_context *brw)
 {
    const GLuint sz = brw->curbe.total_size;
    const GLuint bufsz = sz * 16 * sizeof(GLfloat);
+   enum pipe_error ret;
    GLfloat *buf;
    GLuint i;
 
@@ -267,17 +268,20 @@ static int prepare_curbe_buffer(struct brw_context *brw)
 	  (brw->curbe.need_new_bo ||
 	   brw->curbe.curbe_next_offset + bufsz > brw->curbe.curbe_bo->size))
       {
-	 brw->sws->bo_unreference(brw->curbe.curbe_bo);
-	 brw->curbe.curbe_bo = NULL;
+	 bo_reference(&brw->curbe.curbe_bo, NULL);
       }
 
       if (brw->curbe.curbe_bo == NULL) {
 	 /* Allocate a single page for CURBE entries for this batchbuffer.
 	  * They're generally around 64b.
 	  */
-	 brw->curbe.curbe_bo = brw->sws->bo_alloc(brw->sws, 
-						  BRW_BUFFER_TYPE_CURBE,
-						  4096, 1 << 6);
+	 ret = brw->sws->bo_alloc(brw->sws, 
+                                  BRW_BUFFER_TYPE_CURBE,
+                                  4096, 1 << 6,
+                                  &brw->curbe.curbe_bo);
+         if (ret)
+            return ret;
+
 	 brw->curbe.curbe_next_offset = 0;
       }
 
@@ -313,7 +317,7 @@ static int prepare_curbe_buffer(struct brw_context *brw)
    return 0;
 }
 
-static int emit_curbe_buffer(struct brw_context *brw)
+static enum pipe_error emit_curbe_buffer(struct brw_context *brw)
 {
    GLuint sz = brw->curbe.total_size;