From 433327cb34d38c93313c39938ebc3eb3630b2b2a Mon Sep 17 00:00:00 2001
From: Raph Levien <raph.levien@gmail.com>
Date: Mon, 21 Nov 2022 21:43:03 -0800
Subject: [PATCH] Don't reset query pool twice

When invoked in non robust memory mode (ie not using RenderDriver), both
the render_coarse and render_fine calls reset the query pool, which in
turn causes the fetch of the query pool to hang (in Vulkan).

This is not an issue in robust memory mode because there are two
different query pools, and both should indeed be reset.

This patch makes the second reset conditional on the query pool being
fresh.

Fixes an observed hang with the xilem prototype on Windows.
---
 piet-gpu/src/lib.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/piet-gpu/src/lib.rs b/piet-gpu/src/lib.rs
index 8030234..98347fc 100644
--- a/piet-gpu/src/lib.rs
+++ b/piet-gpu/src/lib.rs
@@ -585,7 +585,9 @@ impl Renderer {
         query_pool: &QueryPool,
         query_start: u32,
     ) {
-        cmd_buf.reset_query_pool(&query_pool);
+        if query_start == 0 {
+            cmd_buf.reset_query_pool(&query_pool);
+        }
         cmd_buf.begin_debug_label("Fine raster");
         let mut pass = cmd_buf.begin_compute_pass(&ComputePassDescriptor::timer(
             &query_pool,