Documentation/video4linux/CQcam.txt - arm/linux-arm64-legacy - Git at Google


            
            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/parport/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.  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.d/*.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


            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
	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/parport/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. 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.d/*.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

	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