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?

2. == Sometimes, when the camera comes back to life, it forgets the
brightness/contrast/etc. settings it used to have. 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.

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.

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?

TIA for any help with these questions,



Gabriel Schulhof
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