i830: Compute initial number of vertices from remaining batch space

In order to prevent an overflow of the batch buffer when emitting
triangles, we need to limit the initial primitive to fit within the
current batch. To do we need to measure the remaining space and thence
compute the maximum number of vertices that fit into that space.

Reported-by: Kurt Roeckx <[email protected]>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41495
Signed-off-by: Chris Wilson <[email protected]>
Reviewed-by: Eric Anholt <[email protected]>
NOTE: This is a candidate for release branches.

1 files changed, 11 insertions, 5 deletions

diff --git a/src/mesa/drivers/dri/i915/intel_render.c b/src/mesa/drivers/dri/i915/intel_render.c
index 432fc7a14b0..a4041bea9ba 100644
--- a/src/mesa/drivers/dri/i915/intel_render.c
+++ b/src/mesa/drivers/dri/i915/intel_render.c
@@ -119,12 +119,14 @@ intelDmaPrimitive(struct intel_context *intel, GLenum prim)
    intel_set_prim(intel, hw_prim[prim]);
 }
 
+#define INTEL_NO_VBO_STATE_RESERVED 1500
+
 static INLINE GLuint intel_get_vb_max(struct intel_context *intel)
 {
    GLuint ret;
 
    if (intel->intelScreen->no_vbo)
-      ret = sizeof(intel->batch.map) - 1500;
+      ret = sizeof(intel->batch.map) - INTEL_NO_VBO_STATE_RESERVED;
    else
       ret = INTEL_VB_SIZE;
    ret /= (intel->vertex_size * 4);
@@ -133,11 +135,15 @@ static INLINE GLuint intel_get_vb_max(struct intel_context *intel)
 
 static INLINE GLuint intel_get_current_max(struct intel_context *intel)
 {
+   GLuint ret;
 
-   if (intel->intelScreen->no_vbo)
-      return intel_get_vb_max(intel);
-   else
-      return (INTEL_VB_SIZE - intel->prim.current_offset) / (intel->vertex_size * 4);
+   if (intel->intelScreen->no_vbo) {
+      ret = intel_batchbuffer_space(intel);
+      ret = ret <= INTEL_NO_VBO_STATE_RESERVED ? 0 : ret - INTEL_NO_VBO_STATE_RESERVED;
+   } else
+      ret = (INTEL_VB_SIZE - intel->prim.current_offset);
+
+   return ret / (intel->vertex_size * 4);
 }
 
 #define LOCAL_VARS struct intel_context *intel = intel_context(ctx)