Mesa (master): anv: Properly fetch partial results in vkGetQueryPoolResults

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Module: Mesa
Branch: master
Commit: af92ce50a7e56d313f5623136d3f09e7c76475fa
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=af92ce50a7e56d313f5623136d3f09e7c76475fa

Author: Brian Ho <brian at brkho.com>
Date:   Sun Jan 26 15:12:11 2020 -0800

anv: Properly fetch partial results in vkGetQueryPoolResults

Currently, fetching the partial results (VK_QUERY_RESULT_PARTIAL_BIT)
of an unavailable occlusion query via vkGetQueryPoolResults can
return invalid values. anv returns slot.end - slot.begin, but in the
case of unavailable queries, slot.end is still at the initial value
of 0. If slot.begin is non-zero, the occlusion count underflows to
a value that is likely outside the acceptable range of the partial
result.

This commit fixes vkGetQueryPoolResults by always returning 0 if the
query is unavailable and the VK_QUERY_RESULT_PARTIAL_BIT is set.

Cc: <mesa-stable at lists.freedesktop.org>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3586>

---

 src/intel/vulkan/genX_query.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/intel/vulkan/genX_query.c b/src/intel/vulkan/genX_query.c
index 04c58871be9..c549b13960b 100644
--- a/src/intel/vulkan/genX_query.c
+++ b/src/intel/vulkan/genX_query.c
@@ -308,8 +308,17 @@ VkResult genX(GetQueryPoolResults)(
       switch (pool->type) {
       case VK_QUERY_TYPE_OCCLUSION: {
          uint64_t *slot = query_slot(pool, firstQuery + i);
-         if (write_results)
-            cpu_write_query_result(pData, flags, idx, slot[2] - slot[1]);
+         if (write_results) {
+            /* From the Vulkan 1.2.132 spec:
+             *
+             *    "If VK_QUERY_RESULT_PARTIAL_BIT is set,
+             *    VK_QUERY_RESULT_WAIT_BIT is not set, and the query’s status
+             *    is unavailable, an intermediate result value between zero and
+             *    the final result value is written to pData for that query."
+             */
+            uint64_t result = available ? slot[2] - slot[1] : 0;
+            cpu_write_query_result(pData, flags, idx, result);
+         }
          idx++;
          break;
       }