bool LinuxDeviceWatcher::Start() {
  // We deliberately return true in the failure paths here because libudev is
  // not a critical component of a Linux system so it may not be present/usable,
  // and we don't want to halt LinuxDeviceManager initialization in such a case.
  if (!libudev_.Load()) {
    LOG(LS_WARNING) << "libudev not present/usable; LinuxDeviceWatcher disabled";
    return true;
  }
  udev_ = libudev_.udev_new()();
  if (!udev_) {
    LOG_ERR(LS_ERROR) << "udev_new()";
    return true;
  }
  // The second argument here is the event source. It can be either "kernel" or
  // "udev", but "udev" is the only correct choice. Apps listen on udev and the
  // udev daemon in turn listens on the kernel.
  udev_monitor_ = libudev_.udev_monitor_new_from_netlink()(udev_, "udev");
  if (!udev_monitor_) {
    LOG_ERR(LS_ERROR) << "udev_monitor_new_from_netlink()";
    return true;
  }
  // We only listen for changes in the video devices. Audio devices are more or
  // less unimportant because receiving device change notifications really only
  // matters for broadcasting updated send/recv capabilities based on whether
  // there is at least one device available, and almost all computers have at
  // least one audio device. Also, PulseAudio device notifications don't come
  // from the udev daemon, they come from the PulseAudio daemon, so we'd only
  // want to listen for audio device changes from udev if using ALSA. For
  // simplicity, we don't bother with any audio stuff at all.
  if (libudev_.udev_monitor_filter_add_match_subsystem_devtype()(
          udev_monitor_, "video4linux", NULL) < 0) {
    LOG_ERR(LS_ERROR) << "udev_monitor_filter_add_match_subsystem_devtype()";
    return true;
  }
  if (libudev_.udev_monitor_enable_receiving()(udev_monitor_) < 0) {
    LOG_ERR(LS_ERROR) << "udev_monitor_enable_receiving()";
    return true;
  }
  static_cast<talk_base::PhysicalSocketServer*>(
      talk_base::Thread::Current()->socketserver())->Add(this);
  registered_ = true;
  return true;
}

if (libudev_.udev_monitor_enable_receiving()(udev_monitor_) < 0) {
    LOG_ERR(LS_ERROR) << "udev_monitor_enable_receiving()";
    return true;
  }

if (!libudev_.Load()) {
    LOG(LS_WARNING) << "libudev not present/usable; LinuxDeviceWatcher disabled";
    return true;
  }

$ wget http://qole.org/repository/pool/fremantle/chromium_5.0.369.2-maemo3_armel.deb
--2015-01-29 11:19:04--  http://qole.org/repository/pool/fremantle/chromium_5.0.369.2-maemo3_armel.deb
Resolving qole.org (qole.org)... 173.236.183.204
Connecting to qole.org (qole.org)|173.236.183.204|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 18757168 (18M) [application/x-debian-package]
Saving to: ‘chromium_5.0.369.2-maemo3_armel.deb’

chromium_5.0.369.2- 100%[=====================>]  17.89M  4.31MB/s   in 6.7s   

2015-01-29 11:19:11 (2.66 MB/s) - ‘chromium_5.0.369.2-maemo3_armel.deb’ saved [18757168/18757168]

$ md5sum chromium_5.0.369.2-maemo3_armel.deb 
b26cbfb9d01160e6ef01f6a89abd4fb0  chromium_5.0.369.2-maemo3_armel.deb