From b7a4faea9b4191e66aaa3bbf43c763aab5678ce3 Mon Sep 17 00:00:00 2001
From: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Date: Tue, 4 Jan 2022 13:04:07 -0500
Subject: [PATCH] zink: skip readback of qbos with no results

this is a no-op and also crashes

Fixes: 93190be1b99 ("zink: rewrite query internals")

Reviewed-by: Hoe Hao Cheng <haochengho12907@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/14397>
---
 src/gallium/drivers/zink/zink_query.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/gallium/drivers/zink/zink_query.c b/src/gallium/drivers/zink/zink_query.c
index 894b68a20f9..9809c253d79 100644
--- a/src/gallium/drivers/zink/zink_query.c
+++ b/src/gallium/drivers/zink/zink_query.c
@@ -459,6 +459,8 @@ get_query_result(struct pipe_context *pctx,
       uint64_t *xfb_results = NULL;
       uint64_t *results;
       bool is_timestamp = query->type == PIPE_QUERY_TIMESTAMP || query->type == PIPE_QUERY_TIMESTAMP_DISJOINT;
+      if (!qbo->num_results)
+         continue;
       results = pipe_buffer_map_range(pctx, qbo->buffer, 0,
                                       (is_timestamp ? 1 : qbo->num_results) * result_size, flags, &xfer);
       if (!results) {