commit 9addb82148c487d6660aecea1af370c2d21d1788
author Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com> Tue Jul 14 17:08:54 2020 -0400
committer Marge Bot <eric+marge@anholt.net> Thu Jul 16 19:59:43 2020 +0000
tree f794fa86c389b1b3e78631edda30325d3f8e8c3b
parent 77bb19eebd1d59c7fc48b41c0f356114f5eab2ef

panfrost: Avoid integer underflow in rt_count_1

If rt_count = 0, this underflows to MAX_MRT. The hw doesn't seem to care
but it's semantically incorrect and confuses pandecode.

Signed-off-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5858>

src/gallium/drivers/panfrost/pan_mfbd.c

diff --git a/src/gallium/drivers/panfrost/pan_mfbd.c b/src/gallium/drivers/panfrost/pan_mfbd.c
index ac890b5..7e9d8cb 100644
--- a/src/gallium/drivers/panfrost/pan_mfbd.c
+++ b/src/gallium/drivers/panfrost/pan_mfbd.c
@@ -482,7 +482,7 @@
                 /* Seems to configure tib size */
                 .unk1 = pan_is_large_tib(batch) ? 0xc80 : 0x1080,
 
-                .rt_count_1 = MALI_POSITIVE(batch->key.nr_cbufs),
+                .rt_count_1 = MALI_POSITIVE(MAX2(batch->key.nr_cbufs, 1)),
                 .rt_count_2 = 4,
         };