On Sat, 2009-05-09 at 18:19 +0200, Kay Sievers wrote:
> On Sat, May 9, 2009 at 16:54, Filippo Argiolas <fargiolas@xxxxxxxxx> wrote:
> > On Sat, May 9, 2009 at 4:24 PM, Filippo Argiolas <fargiolas@xxxxxxxxx> wrote:
> >> On Sat, May 9, 2009 at 1:49 PM, Kay Sievers <kay.sievers@xxxxxxxx> wrote:
> >>> I've committed a merge of both versions.
> >>
> >> Great :)
> >> I still don't see it though in the udev (nor udev-extras) git repositories.
>
> Yeah, seems the master -> public rsync is really slow the last days.
>
> > Now it's ok. I forgot the email in the copyright line, you can put
> > <filippo.argiolas@xxxxxxxxx> if you want.
>
> Done.
Here is small hack using libudev, that enumerates all capture-capable
video devices, and listens for new devices connected, or devices going
away.
It builds with:
gcc -Wall -o v4l-monitor v4l-monitor.c -ludev
And prints when started the built-in camera:
$ ./v4l-monitor
UVC Camera (17ef:4807) (/dev/video0)
and while new devices are plugged/unplugged:
UVC Camera (046d:09a4) (/dev/video1) (add)
OV511+ USB Camera (/dev/video2) (add)
UVC Camera (046d:09a4) (/dev/video1) (remove)
OV511+ USB Camera (/dev/video2) (remove)
OV511+ USB Camera (/dev/video1) (add)
UVC Camera (046d:09a4) (/dev/video2) (add)
...
Cheers,
Kay
/*
* enumerate and monitor v4l devices
*
* Copyright (C) 2009 Kay Sievers <kay.sievers@xxxxxxxx>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*/
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <getopt.h>
#include <syslog.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/select.h>
#define LIBUDEV_I_KNOW_THE_API_IS_SUBJECT_TO_CHANGE 1
#include "libudev.h"
int main(int argc, char *argv[])
{
struct udev *udev;
struct udev_monitor *monitor;
struct udev_enumerate *enumerate;
struct udev_list_entry *list_entry;
/* libudev context */
udev = udev_new();
/* connect to event source */
monitor = udev_monitor_new_from_netlink(udev, "udev");
/* install subsytem filter, we will not wake-up for other events */
udev_monitor_filter_add_match_subsystem_devtype(monitor, "video4linux", NULL);
/* listen to events, and buffer them */
udev_monitor_enable_receiving(monitor);
/* prepare a device scan */
enumerate = udev_enumerate_new(udev);
/* filter for video devices */
udev_enumerate_add_match_subsystem(enumerate,"video4linux");
/* filter for capture capable devices */
udev_enumerate_add_match_property(enumerate, "ID_V4L_CAPABILITIES", "*:capture:*");
/* retrieve the list */
udev_enumerate_scan_devices(enumerate);
/* print devices */
udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(enumerate)) {
struct udev_device *device;
device = udev_device_new_from_syspath(udev_enumerate_get_udev(enumerate),
udev_list_entry_get_name(list_entry));
if (device == NULL)
continue;
printf("%s (%s)\n",
udev_device_get_property_value(device, "ID_V4L_PRODUCT"),
udev_device_get_devnode(device));
udev_device_unref(device);
}
udev_enumerate_unref(enumerate);
/* process events */
while (1) {
struct pollfd pfd[2];
struct udev_device *device;
pfd[0].fd = udev_monitor_get_fd(monitor);
pfd[0].events = POLLIN;
pfd[1].fd = STDIN_FILENO;
pfd[1].events = POLLIN;
if (poll(pfd, 2, -1) < 1)
continue;
if (pfd[0].revents & POLLIN) {
const char *cap;
/* get device from event */
device = udev_monitor_receive_device(monitor);
if (device == NULL)
continue;
/* filter capture-capable devices */
cap = udev_device_get_property_value(device, "ID_V4L_CAPABILITIES");
if (cap == NULL || strstr(":capture:", cap) == NULL)
continue;
/* print device */
printf("%s (%s) (%s)\n",
udev_device_get_property_value(device, "ID_V4L_PRODUCT"),
udev_device_get_devnode(device),
udev_device_get_action(device));
udev_device_unref(device);
}
/* exit the loop on console input */
if (pfd[1].revents & POLLIN)
break;
}
udev_monitor_unref(monitor);
udev_unref(udev);
return 0;
}
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