sna: Tweak number of threads for short areas

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/sna/sna_threads.c b/src/sna/sna_threads.c
index 83b180f8..f9c6b1e8 100644
--- a/src/sna/sna_threads.c
+++ b/src/sna/sna_threads.c
@@ -259,8 +259,8 @@ int sna_use_threads(int width, int height, int threshold)
 	if (max_threads <= 0)
 		return 1;
 
-	if (height <= max_threads)
-		return height;
+	if (height <= 1)
+		return 1;
 
 	if (width < 128)
 		height /= 128/width;
@@ -271,6 +271,9 @@ int sna_use_threads(int width, int height, int threshold)
 
 	if (num_threads > max_threads)
 		num_threads = max_threads;
+	if (num_threads > height)
+		num_threads = height;
+
 	return num_threads;
 }