[patch v4l-utils 2/2] v4l2-ctl: fix bugs found in streaming_set_cap2out

[Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>]

When exporting buffers from a capture device
to an output device. There are several bugs:
1. The bytesused are set from the exported buffer,
the value might be bigger than the length of the output buffer.
2. The file descriptor field 'm.fd' in 'struct v4l2_buffer' is not set.

This patch fix those issues.

Testing:

modprobe vimc
modprobe vivid

//configure vimc pipeline
media-ctl -d platform:vimc -V '"Sensor A":0[fmt:SBGGR8_1X8/640x480]'
media-ctl -d platform:vimc -V '"Debayer A":0[fmt:SBGGR8_1X8/640x480]'
media-ctl -d platform:vimc -V '"Sensor B":0[fmt:SBGGR8_1X8/640x480]'
media-ctl -d platform:vimc -V '"Debayer B":0[fmt:SBGGR8_1X8/640x480]'

v4l2-ctl -z platform:vimc -d "RGB/YUV Capture" -v width=1920,height=1440
v4l2-ctl -z platform:vimc -d "Raw Capture 0" -v pixelformat=BA81
v4l2-ctl -z platform:vimc -d "Raw Capture 1" -v pixelformat=BA81

// export buffers from vimc capture device (/dev/video2) to vivid output device (/dev/video4)
v4l2-ctl -d2 --stream-mmap --out-device /dev/video4 --stream-out-dmabuf

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@xxxxxxxxxxxxx>
---
 utils/v4l2-ctl/v4l2-ctl-streaming.cpp | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
index 0f28a537..432f1cc6 100644
--- a/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
+++ b/utils/v4l2-ctl/v4l2-ctl-streaming.cpp
@@ -1499,6 +1499,11 @@ static int do_handle_out(cv4l_fd &fd, cv4l_queue &q, FILE *fin, cv4l_buffer *cap
 	if (cap) {
 		buf.s_index(cap->g_index());
 
+		if (fd.querybuf(buf)) {
+			fprintf(stderr, "%s fd.querybuf failed\n", __func__);
+			return QUEUE_ERROR;
+		}
+
 		for (unsigned j = 0; j < buf.g_num_planes(); j++) {
 			unsigned data_offset = cap->g_data_offset(j);
 
@@ -1507,8 +1512,17 @@ static int do_handle_out(cv4l_fd &fd, cv4l_queue &q, FILE *fin, cv4l_buffer *cap
 				buf.s_bytesused(cap->g_bytesused(j) - data_offset, j);
 				buf.s_data_offset(0, j);
 			} else if (q.g_memory() == V4L2_MEMORY_DMABUF) {
-				buf.s_bytesused(cap->g_bytesused(j), j);
+				__u32 bytesused = cap->g_bytesused(j);
+				/*
+				 * bytesused comes from the exported cap buffer
+				 * but the length of the out buffer might be smaller
+				 * so take the smaller of the two
+				 */
+				if(bytesused > buf.g_length(j))
+					bytesused = buf.g_length(j);
+				buf.s_bytesused(bytesused, j);
 				buf.s_data_offset(data_offset, j);
+				buf.s_fd(q.g_fd(buf.g_index(), j));
 			}
 		}
 	} else {
-- 
2.17.1