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Based on kernel version 3.2. Page generated on 2012-01-05 23:29 EST.

	c-qcam - Connectix Color QuickCam video4linux kernel driver
	
	Copyright (C) 1999  Dave Forrest  <drf5n@virginia.edu>
			    released under GNU GPL.
	
	1999-12-08 Dave Forrest, written with kernel version 2.2.12 in mind
	
	
	Table of Contents
	
	1.0 Introduction
	2.0 Compilation, Installation, and Configuration
	3.0 Troubleshooting
	4.0 Future Work / current work arounds
	9.0 Sample Program, v4lgrab
	10.0 Other Information
	
	
	1.0 Introduction
	
	  The file ../../drivers/media/video/c-qcam.c is a device driver for
	the Logitech (nee Connectix) parallel port interface color CCD camera.
	This is a fairly inexpensive device for capturing images.  Logitech
	does not currently provide information for developers, but many people
	have engineered several solutions for non-Microsoft use of the Color
	Quickcam.
	
	1.1 Motivation
	
	  I spent a number of hours trying to get my camera to work, and I
	hope this document saves you some time.  My camera will not work with
	the 2.2.13 kernel as distributed, but with a few patches to the
	module, I was able to grab some frames. See 4.0, Future Work.
	
	
	
	2.0 Compilation, Installation, and Configuration
	
	  The c-qcam depends on parallel port support, video4linux, and the
	Color Quickcam.  It is also nice to have the parallel port readback
	support enabled. I enabled these as modules during the kernel
	configuration.  The appropriate flags are:
	
	    CONFIG_PRINTER       M    for lp.o, parport.o parport_pc.o modules
	    CONFIG_PNP_PARPORT   M for autoprobe.o IEEE1284 readback module
	    CONFIG_PRINTER_READBACK M for parport_probe.o IEEE1284 readback module
	    CONFIG_VIDEO_DEV     M    for videodev.o video4linux module
	    CONFIG_VIDEO_CQCAM   M    for c-qcam.o  Color Quickcam module
	
	  With these flags, the kernel should compile and install the modules.
	To record and monitor the compilation, I use:
	
	 (make zlilo ; \
	  make modules; \
	  make modules_install ;
	  depmod -a ) &>log &
	 less log  # then a capital 'F' to watch the progress
	
	But that is my personal preference.
	
	2.2 Configuration
	
	  The configuration requires module configuration and device
	configuration.  I like kmod or kerneld process with the
	/etc/modprobe.conf file so the modules can automatically load/unload as
	they are used.  The video devices could already exist, be generated
	using MAKEDEV, or need to be created.  The following sections detail
	these procedures.
	
	
	2.1 Module Configuration
	
	  Using modules requires a bit of work to install and pass the
	parameters.  Understand that entries in /etc/modprobe.conf of:
	
	   alias parport_lowlevel parport_pc
	   options parport_pc io=0x378 irq=none
	   alias char-major-81 videodev
	   alias char-major-81-0 c-qcam
	
	will cause the kmod/modprobe to do certain things.  If you are
	using kmod, then a request for a 'char-major-81-0' will cause
	the 'c-qcam' module to load.  If you have other video sources with
	modules, you might want to assign the different minor numbers to
	different modules.
	
	2.2 Device Configuration
	
	  At this point, we need to ensure that the device files exist.
	Video4linux used the /dev/video* files, and we want to attach the
	Quickcam to one of these.
	
	   ls -lad /dev/video*  # should produce a list of the video devices
	
	If the video devices do not exist, you can create them with:
	
	  su
	  cd /dev
	  for ii in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ; do
	    mknod video$ii c 81 $ii   # char-major-81-[0-16]
	    chown root.root video$ii  # owned by root
	    chmod 600 video$ii        # read/writable by root only
	  done
	
	  Lots of people connect video0 to video and bttv, but you might want
	your c-qcam to mean something more:
	
	   ln -s video0 c-qcam  # make /dev/c-qcam a working file
	   ln -s c-qcam video   # make /dev/c-qcam your default video source
	
	  But these are conveniences.  The important part is to make the proper
	special character files with the right major and minor numbers.  All
	of the special device files are listed in ../devices.txt.  If you
	would like the c-qcam readable by non-root users, you will need to
	change the permissions.
	
	3.0 Troubleshooting
	
	  If the sample program below, v4lgrab, gives you output then
	everything is working.
	
	    v4lgrab | wc # should give you a count of characters
	
	  Otherwise, you have some problem.
	
	  The c-qcam is IEEE1284 compatible, so if you are using the proc file
	system (CONFIG_PROC_FS), the parallel printer support
	(CONFIG_PRINTER), the IEEE 1284 system,(CONFIG_PRINTER_READBACK), you
	should be able to read some identification from your quickcam with
	
		 modprobe -v parport
		 modprobe -v parport_probe
		 cat /proc/parport/PORTNUMBER/autoprobe
	Returns:
	  CLASS:MEDIA;
	  MODEL:Color QuickCam 2.0;
	  MANUFACTURER:Connectix;
	
	  A good response to this indicates that your color quickcam is alive
	and well.  A common problem is that the current driver does not
	reliably detect a c-qcam, even though one is attached.  In this case,
	
	     modprobe -v c-qcam
	or
	     insmod -v c-qcam
	
	  Returns a message saying "Device or resource busy"  Development is
	currently underway, but a workaround is to patch the module to skip
	the detection code and attach to a defined port.  Check the
	video4linux mailing list and archive for more current information.
	
	3.1 Checklist:
	
	  Can you get an image?
		    v4lgrab >qcam.ppm ; wc qcam.ppm ; xv qcam.ppm
	
	  Is a working c-qcam connected to the port?
		    grep ^ /proc/parport/?/autoprobe
	
	  Do the /dev/video* files exist?
		    ls -lad /dev/video
	
	  Is the c-qcam module loaded?
		    modprobe -v c-qcam ; lsmod
	
	  Does the camera work with alternate programs? cqcam, etc?
	
	
	
	
	4.0 Future Work / current workarounds
	
	  It is hoped that this section will soon become obsolete, but if it
	isn't, you might try patching the c-qcam module to add a parport=xxx
	option as in the bw-qcam module so you can specify the parallel port:
	
	       insmod -v c-qcam parport=0
	
	And bypass the detection code, see ../../drivers/char/c-qcam.c and
	look for the 'qc_detect' code and call.
	
	  Note that there is work in progress to change the video4linux API,
	this work is documented at the video4linux2 site listed below.
	
	
	9.0 --- A sample program using v4lgrabber,
	
	v4lgrab is a simple image grabber that will copy a frame from the
	first video device, /dev/video0 to standard output in portable pixmap
	format (.ppm)  To produce .jpg output, you can use it like this:
	'v4lgrab | convert - c-qcam.jpg'
	
	
	10.0 --- Other Information
	
	Use the ../../Maintainers file, particularly the  VIDEO FOR LINUX and PARALLEL
	PORT SUPPORT sections
	
	The video4linux page:
	  http://linuxtv.org
	
	The V4L2 API spec:
	  http://v4l2spec.bytesex.org/
	
	Some web pages about the quickcams:
	   http://www.pingouin-land.com/howto/QuickCam-HOWTO.html
	
	   http://www.crynwr.com/qcpc/            QuickCam Third-Party Drivers
	   http://www.crynwr.com/qcpc/re.html     Some Reverse Engineering
	   http://www.wirelesscouch.net/software/gqcam/   v4l client
	   http://phobos.illtel.denver.co.us/pub/qcread/ doesn't use v4l
	   ftp://ftp.cs.unm.edu/pub/chris/quickcam/   Has lots of drivers
	   http://www.cs.duke.edu/~reynolds/quickcam/ Has lots of information
	

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