picnoir/Systemd
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

v4l_id: use device_caps if available

Browse source 
According to the specification[1] the 'capabilities' describe the physical
device as a whole and the 'device_caps' describe the current device node.
The existence of 'device_caps' is indicated by the V4L2_CAP_DEVICE_CAPS
capability flag.
Use the 'device_caps' if available to generate the correct
ID_V4L_CAPABILITIES for the current device node.

This is relevant for UVC devices with current kernels: Two /dev/videoX
devices exist for those. One for video and one for metadata. The
 V4L2_CAP_VIDEO_CAPTURE flag is present in the 'capabilities' for both
device nodes but only in the 'device_caps' of the video device node.

Without this, the ID_V4L_CAPABILITIES of the metadata device node
incorrectly contains 'capture'.

[1] https://www.linuxtv.org/downloads/v4l-dvb-apis-new/uapi/v4l/vidioc-querycap.html
This commit is contained in:
Michael Olbrich 2019-02-03 10:52:02 +01:00 committed by Lennart Poettering
parent eca3d5d567
commit 646876105f
1 changed files with 13 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
src/udev/v4l_id/v4l_id.c
View file

@ -64,22 +64,27 @@ int main(int argc, char *argv[]) {
return 3;
if (ioctl(fd, VIDIOC_QUERYCAP, &v2cap) == 0) {
int capabilities;
printf("ID_V4L_VERSION=2\n");
printf("ID_V4L_PRODUCT=%s\n", v2cap.card);
printf("ID_V4L_CAPABILITIES=:");
if ((v2cap.capabilities & V4L2_CAP_VIDEO_CAPTURE) > 0 ||
(v2cap.capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE) > 0)
if (v2cap.capabilities & V4L2_CAP_DEVICE_CAPS)
capabilities = v2cap.device_caps;
else
capabilities = v2cap.capabilities;
if ((capabilities & V4L2_CAP_VIDEO_CAPTURE) > 0 ||
(capabilities & V4L2_CAP_VIDEO_CAPTURE_MPLANE) > 0)
printf("capture:");
if ((v2cap.capabilities & V4L2_CAP_VIDEO_OUTPUT) > 0 ||
(v2cap.capabilities & V4L2_CAP_VIDEO_OUTPUT_MPLANE) > 0)
if ((capabilities & V4L2_CAP_VIDEO_OUTPUT) > 0 ||
(capabilities & V4L2_CAP_VIDEO_OUTPUT_MPLANE) > 0)
printf("video_output:");
if ((v2cap.capabilities & V4L2_CAP_VIDEO_OVERLAY) > 0)
if ((capabilities & V4L2_CAP_VIDEO_OVERLAY) > 0)
printf("video_overlay:");
if ((v2cap.capabilities & V4L2_CAP_AUDIO) > 0)
if ((capabilities & V4L2_CAP_AUDIO) > 0)
printf("audio:");
if ((v2cap.capabilities & V4L2_CAP_TUNER) > 0)
if ((capabilities & V4L2_CAP_TUNER) > 0)
printf("tuner:");
if ((v2cap.capabilities & V4L2_CAP_RADIO) > 0)
if ((capabilities & V4L2_CAP_RADIO) > 0)
printf("radio:");
printf("\n");
}