nv30: reset fragprog bufctx at bind time

A clear will do a partial validate, which will in turn reference all the
buffers in the bufctx again. However the fragprog last validated might
have already been deleted. So reset the bufctx when updating state.

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>

src/gallium/drivers/nouveau/nv30/nv30_fragprog.c

@@ -165,8 +165,15 @@ static void
 nv30_fp_state_bind(struct pipe_context *pipe, void *hwcso)
 {
    struct nv30_context *nv30 = nv30_context(pipe);
+   struct nv30_fragprog *fp = hwcso;
 
-   nv30->fragprog.program = hwcso;
+   /* reset the bucftx so that we don't keep a dangling reference to the fp
+    * code
+    */
+   if (fp != nv30->state.fragprog)
+      PUSH_RESET(nv30->base.pushbuf, BUFCTX_FRAGPROG);
+
+   nv30->fragprog.program = fp;
    nv30->dirty |= NV30_NEW_FRAGPROG;
 }