On Friday 13 March 2009 00:34:43 Andy Walls wrote: > On Thu, 2009-03-12 at 10:49 +0100, Gregor Fuis wrote: > > On Thu, Mar 12, 2009 at 10:28 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > >> Hello, > > >> > > >> Is it possible to disable v4l2-ctl aplication logging into > > >> /var/log/messages. > > >> I am using it to control and monitor my PVR 150 cards and every time > > >> I run v4l2-ctl -d /dev/video0 --log-status all output is logged into > > >> /var/log/messages and some other linux log files. > > > > > > All --log-status does is to tell the driver to show it's status in > > > the kernel log for debugging purposes. It cannot and should not be > > > relied upon for monitoring/controlling a driver. > > > > > > What do you need it for anyway? > > > > I am just monitoring if signal is present on tuner, and what signal > > format is detected. > > These two lines: > > cx25840 1-0044: Video signal: not present > > cx25840 1-0044: Detected format: PAL-Nc > > I run this every minute and it is really annoying to have all this in > > my system logs. > > Is it possible to modify v4l2-ctl source to disable system logging? > > $ v4l2-ctl -d /dev/video0 -T > > which calls the VIDIOC_G_TUNER ioctl(), can be used to tell you if a > signal is present: > > Tuner: > Name : cx18 TV Tuner > Capabilities : 62.5 kHz multi-standard stereo lang1 lang2 > Frequency range : 44.0 MHz - 958.0 MHz > Signal strength/AFC : 0%/-187500 > Current audio mode : lang1 > Available subchannels: mono > > Signal strength will be 0% or 100% - both the cx18 driver and the > cx25840 driver behave the same in this regard. > > AFAICT, other than --log-status (the VIDIOC_LOG_STATUS ioctl()) which > always writes to the system logs, there is no way for a non-root user to > read out the Video standard detected by the CX25843 hardware. That > would require a change to the driver(s) and maybe an API change (I'm not > sure). There is a VIDIOC_QUERYSTD ioctl. However, neither ivtv nor cx25840 supports that. I've always thought that that would be a useful addition, but never got around to implementing it. You are the first one for whom such an ioctl would actually be useful, Gregor :-) It should be fairly easy to add this, but I really don't have the time for this I'm afraid. Regards, Hans -- Hans Verkuil - video4linux developer - sponsored by TANDBERG -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
