Hi Gabriel, On Tuesday 30 December 2008, Gabriel Schulhof wrote: > Hi! > > I have just bought such a camera, and it worked out of the box with a > laptop running Fedora 9. Excellent! > > The camera has to work for a person who is over 60 years old and is only > now (very enthusiastic about) learning to use a computer. Thus, I would > like to configure a few things to make the camera work more reliably: > > 1. == This is a bit of a bug report: after recovering from hibernation, > the camera has to be unplugged/plugged back in. Does/Will uvcvideo have > hibernate/suspend support?
The uvcvideo driver should already support suspend/resume. Please give us a more detailed report of what goes wrong. > 2. == Sometimes, when the camera comes back to life, it forgets the > brightness/contrast/etc. settings it used to have. The driver is supposed to restore control values when a device is resumed (I'm not sure if the camera itself is supposed to retain those settings or not, I guess it depends if the computer removes power from the USB ports during suspend). Please have a look at the kernel log (using dmesg) when this happens to see if the driver prints any error or informational message. > Thus, I was wondering > if there is a console-based utility that I can run, setting reasonable > default values either automatically or at the click of a button. > Currently, I can use ekiga or xawtv to set brightness, contrast, and > colour intensity. However, I think it's too complicated to teach. Thus, > the utility would have to accept brightness/contrast/colour intensity > values on the command line and (probably) use v4l2 to set the values. > > For example the quickcam messenger driver had a utility called qc-set, > whose command line allowed me to specify values for brightness, contrast, > colour, etc. and which would set up the camera accordingly. The v4l2-ctl utility (found in the v4l-dvb repository on http://linuxtv.org/) can be used to set V4L2 controls on the command line. > Alternatively, can I specify such values using module parameters? I > noticed that uvcvideo (v0.1.0, according to modinfo) doesn't have any > brightness/contrast/etc. module parameters: > > parm: quirks:Forced device quirks (uint) > parm: trace:Trace level bitmask (uint) > > Is it possible to add such parameters to the module so as to specify > default brightness/contrast/etc. values? I realize that the module may be > responsible for multiple webcams, so addressing the > brightness/contrast/etc. values to the right webcam may not be a trivial > task. Module parameters are not really suited for that job. You should use a command line application instead, possibly in relation with udev/hal. > 3. == I have observed that, after multiple hibernate/resume cycles, > /dev/video0 stops working. Even after > > 1. Unplugging the camera > 2. modprobe -r uvcvideo > 3. Plugging in the camera > > the resulting /dev/video0 does not work. mplayer tv:// says: > > MPlayer dev-SVN-r27514-4.3.0 (C) 2000-2008 MPlayer Team > CPU: Mobile AMD Sempron(tm) Processor 2600+ (Family: 15, Model: 8, > Stepping: 2) > CPUflags: MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 1 > Compiled with runtime CPU detection. > mplayer: could not connect to socket > mplayer: No such file or directory > Failed to open LIRC support. You will not be able to use your remote > control. > > Playing tv://. > TV file format detected. > Selected driver: v4l2 > name: Video 4 Linux 2 input > author: Martin Olschewski <[email protected]> > comment: first try, more to come ;-) > v4l2: your device driver does not support VIDIOC_G_STD ioctl, > VIDIOC_G_PARM was used instead. > Selected device: UVC Camera (046d:09a4) > Capabilites: video capture streaming > supported norms: > inputs: 0 = Camera 1; > Current input: 0 > Current format: MJPEG > v4l2: ioctl set format failed: Input/output error > v4l2: ioctl set mute failed: Invalid argument > v4l2: 0 frames successfully processed, 0 frames dropped. > > Is there a way to reset the camera so that it continues to work after > arbitrary numbers of hibernate/resume cycles? Please check the kernel log for error messages that could help diagnose this problem. Best regards, Laurent Pinchart _______________________________________________ Linux-uvc-devel mailing list [email protected] https://lists.berlios.de/mailman/listinfo/linux-uvc-devel
