[Mesa-dev] [PATCH] i965: Ensure that all necessary state is re-emitted if we run out of aperture.

[Paul Berry]

Prior to this patch, if we ran out of aperture space during
brw_try_draw_prims(), we would rewind the batch buffer pointer
(potentially throwing some state that may have been emitted by
brw_upload_state()), flush the batch, and then try again.  However, we
wouldn't reset the dirty bits to the state they had before the call to
brw_upload_state().  As a result, when we tried again, there was a
danger that we wouldn't re-emit all the necessary state.  (Note: prior
to the introduction of hardware contexts, this wasn't a problem
because flushing the batch forced all state to be re-emitted).

This patch fixes the problem by leaving the dirty bits set at the end
of brw_upload_state(); we only clear them after we have determined
that we don't need to rewind the batch buffer.

Cc: 10.0 9.2 <mesa-stable at lists.freedesktop.org>
---
 src/mesa/drivers/dri/i965/brw_draw.c         |  6 ++++++
 src/mesa/drivers/dri/i965/brw_state.h        |  1 +
 src/mesa/drivers/dri/i965/brw_state_upload.c | 14 ++++++++++++++
 3 files changed, 21 insertions(+)

diff --git a/src/mesa/drivers/dri/i965/brw_draw.c b/src/mesa/drivers/dri/i965/brw_draw.c
index b898cd3..ec56a21 100644
--- a/src/mesa/drivers/dri/i965/brw_draw.c
+++ b/src/mesa/drivers/dri/i965/brw_draw.c
@@ -499,6 +499,12 @@ retry:
 	    }
 	 }
       }
+
+      /* Now that we know we haven't run out of aperture space, we can safely
+       * reset the dirty bits.
+       */
+      if (brw->state.dirty.brw)
+         brw_clear_dirty_bits(brw);
    }
 
    if (brw->always_flush_batch)
diff --git a/src/mesa/drivers/dri/i965/brw_state.h b/src/mesa/drivers/dri/i965/brw_state.h
index a148125..e9428fb 100644
--- a/src/mesa/drivers/dri/i965/brw_state.h
+++ b/src/mesa/drivers/dri/i965/brw_state.h
@@ -143,6 +143,7 @@ brw_depthbuffer_format(struct brw_context *brw);
  * brw_state.c
  */
 void brw_upload_state(struct brw_context *brw);
+void brw_clear_dirty_bits(struct brw_context *brw);
 void brw_init_state(struct brw_context *brw);
 void brw_destroy_state(struct brw_context *brw);
 
diff --git a/src/mesa/drivers/dri/i965/brw_state_upload.c b/src/mesa/drivers/dri/i965/brw_state_upload.c
index 1eb3a79..7490df4 100644
--- a/src/mesa/drivers/dri/i965/brw_state_upload.c
+++ b/src/mesa/drivers/dri/i965/brw_state_upload.c
@@ -573,6 +573,20 @@ void brw_upload_state(struct brw_context *brw)
 	 fprintf(stderr, "\n");
       }
    }
+}
+
 
+/**
+ * Clear dirty bits to account for the fact that the state emitted by
+ * brw_upload_state() has been committed to the hardware.  This is a separate
+ * call from brw_upload_state() because it's possible that after the call to
+ * brw_upload_state(), we will discover that we've run out of aperture space,
+ * and need to rewind the batch buffer to the state it had before the
+ * brw_upload_state() call.
+ */
+void
+brw_clear_dirty_bits(struct brw_context *brw)
+{
+   struct brw_state_flags *state = &brw->state.dirty;
    memset(state, 0, sizeof(*state));
 }
-- 
1.8.5.2