[PATCH 5.10 011/142] media: cedrus: Fix H264 decoding

Greg Kroah-Hartman
2021-02-02T13:51:01Z

From: Jernej Skrabec <jernej.skrabec@siol.net>

commit 73bc0b0c2a96b31199da0ce6c3d04be81ef73bb9 upstream.

During H264 API overhaul subtle bug was introduced Cedrus driver.
Progressive references have both, top and bottom reference flags set.
Cedrus reference list expects only bottom reference flag and only when
interlaced frames are decoded. However, due to a bug in Cedrus check,
exclusivity is not tested and that flag is set also for progressive
references. That causes "jumpy" background with many videos.

Fix that by checking that only bottom reference flag is set in control
and nothing else.

Tested-by: Andre Heider <a.heider@gmail.com>
Fixes: cfc8c3ed533e ("media: cedrus: h264: Properly configure reference field")
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Cc: <stable@vger.kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/staging/media/sunxi/cedrus/cedrus_h264.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
+++ b/drivers/staging/media/sunxi/cedrus/cedrus_h264.c
@@ -203,7 +203,7 @@ static void _cedrus_write_ref_list(struc
position = cedrus_buf->codec.h264.position;

sram_array[i] |= position << 1;
- if (ref_list[i].fields & V4L2_H264_BOTTOM_FIELD_REF)
+ if (ref_list[i].fields == V4L2_H264_BOTTOM_FIELD_REF)
sram_array[i] |= BIT(0);
}