Documentation/video4linux/CQcam.txt

   1 c-qcam - Connectix Color QuickCam video4linux kernel driver
   2
   3 Copyright (C) 1999  Dave Forrest  <drf5n@virginia.edu>
   4                     released under GNU GPL.
   5
   6 1999-12-08 Dave Forrest, written with kernel version 2.2.12 in mind
   7
   8
   9 Table of Contents
  10
  11 1.0 Introduction
  12 2.0 Compilation, Installation, and Configuration
  13 3.0 Troubleshooting
  14 4.0 Future Work / current work arounds
  15 9.0 Sample Program, v4lgrab
  16 10.0 Other Information
  17
  18
  19 1.0 Introduction
  20
  21   The file ../../drivers/media/video/c-qcam.c is a device driver for
  22 the Logitech (nee Connectix) parallel port interface color CCD camera.
  23 This is a fairly inexpensive device for capturing images.  Logitech
  24 does not currently provide information for developers, but many people
  25 have engineered several solutions for non-Microsoft use of the Color
  26 Quickcam.
  27
  28 1.1 Motivation
  29
  30   I spent a number of hours trying to get my camera to work, and I
  31 hope this document saves you some time.  My camera will not work with
  32 the 2.2.13 kernel as distributed, but with a few patches to the
  33 module, I was able to grab some frames. See 4.0, Future Work.
  34
  35
  36
  37 2.0 Compilation, Installation, and Configuration
  38
  39   The c-qcam depends on parallel port support, video4linux, and the
  40 Color Quickcam.  It is also nice to have the parallel port readback
  41 support enabled. I enabled these as modules during the kernel
  42 configuration.  The appropriate flags are:
  43
  44     CONFIG_PRINTER       M    for lp.o, parport.o parport_pc.o modules
  45     CONFIG_PNP_PARPORT   M for autoprobe.o IEEE1284 readback module
  46     CONFIG_PRINTER_READBACK M for parport_probe.o IEEE1284 readback module
  47     CONFIG_VIDEO_DEV     M    for videodev.o video4linux module
  48     CONFIG_VIDEO_CQCAM   M    for c-qcam.o  Color Quickcam module
  49
  50   With these flags, the kernel should compile and install the modules.
  51 To record and monitor the compilation, I use:
  52
  53  (make zlilo ; \
  54   make modules; \
  55   make modules_install ;
  56   depmod -a ) &>log &
  57  less log  # then a capital 'F' to watch the progress
  58
  59 But that is my personal preference.
  60
  61 2.2 Configuration
  62
  63   The configuration requires module configuration and device
  64 configuration.  I like kmod or kerneld process with the
  65 /etc/modprobe.conf file so the modules can automatically load/unload as
  66 they are used.  The video devices could already exist, be generated
  67 using MAKEDEV, or need to be created.  The following sections detail
  68 these procedures.
  69
  70
  71 2.1 Module Configuration
  72
  73   Using modules requires a bit of work to install and pass the
  74 parameters.  Understand that entries in /etc/modprobe.conf of:
  75
  76    alias parport_lowlevel parport_pc
  77    options parport_pc io=0x378 irq=none
  78    alias char-major-81 videodev
  79    alias char-major-81-0 c-qcam
  80
  81 will cause the kmod/modprobe to do certain things.  If you are
  82 using kmod, then a request for a 'char-major-81-0' will cause
  83 the 'c-qcam' module to load.  If you have other video sources with
  84 modules, you might want to assign the different minor numbers to
  85 different modules.
  86
  87 2.2 Device Configuration
  88
  89   At this point, we need to ensure that the device files exist.
  90 Video4linux used the /dev/video* files, and we want to attach the
  91 Quickcam to one of these.
  92
  93    ls -lad /dev/video*  # should produce a list of the video devices
  94
  95 If the video devices do not exist, you can create them with:
  96
  97   su
  98   cd /dev
  99   for ii in 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 ; do
 100     mknod video$ii c 81 $ii   # char-major-81-[0-16]
 101     chown root.root video$ii  # owned by root
 102     chmod 600 video$ii        # read/writable by root only
 103   done
 104
 105   Lots of people connect video0 to video and bttv, but you might want
 106 your c-qcam to mean something more:
 107
 108    ln -s video0 c-qcam  # make /dev/c-qcam a working file
 109    ln -s c-qcam video   # make /dev/c-qcam your default video source
 110
 111   But these are conveniences.  The important part is to make the proper
 112 special character files with the right major and minor numbers.  All
 113 of the special device files are listed in ../devices.txt.  If you
 114 would like the c-qcam readable by non-root users, you will need to
 115 change the permissions.
 116
 117 3.0 Troubleshooting
 118
 119   If the sample program below, v4lgrab, gives you output then
 120 everything is working.
 121
 122     v4lgrab | wc # should give you a count of characters
 123
 124   Otherwise, you have some problem.
 125
 126   The c-qcam is IEEE1284 compatible, so if you are using the proc file
 127 system (CONFIG_PROC_FS), the parallel printer support
 128 (CONFIG_PRINTER), the IEEE 1284 system,(CONFIG_PRINTER_READBACK), you
 129 should be able to read some identification from your quickcam with
 130
 131          modprobe -v parport
 132          modprobe -v parport_probe
 133          cat /proc/parport/PORTNUMBER/autoprobe
 134 Returns:
 135   CLASS:MEDIA;
 136   MODEL:Color QuickCam 2.0;
 137   MANUFACTURER:Connectix;
 138
 139   A good response to this indicates that your color quickcam is alive
 140 and well.  A common problem is that the current driver does not
 141 reliably detect a c-qcam, even though one is attached.  In this case,
 142
 143      modprobe -v c-qcam
 144 or
 145      insmod -v c-qcam
 146
 147   Returns a message saying "Device or resource busy"  Development is
 148 currently underway, but a workaround is to patch the module to skip
 149 the detection code and attach to a defined port.  Check the
 150 video4linux mailing list and archive for more current information.
 151
 152 3.1 Checklist:
 153
 154   Can you get an image?
 155             v4lgrab >qcam.ppm ; wc qcam.ppm ; xv qcam.ppm
 156
 157   Is a working c-qcam connected to the port?
 158             grep ^ /proc/parport/?/autoprobe
 159
 160   Do the /dev/video* files exist?
 161             ls -lad /dev/video
 162
 163   Is the c-qcam module loaded?
 164             modprobe -v c-qcam ; lsmod
 165
 166   Does the camera work with alternate programs? cqcam, etc?
 167
 168
 169
 170
 171 4.0 Future Work / current workarounds
 172
 173   It is hoped that this section will soon become obsolete, but if it
 174 isn't, you might try patching the c-qcam module to add a parport=xxx
 175 option as in the bw-qcam module so you can specify the parallel port:
 176
 177        insmod -v c-qcam parport=0
 178
 179 And bypass the detection code, see ../../drivers/char/c-qcam.c and
 180 look for the 'qc_detect' code and call.
 181
 182   Note that there is work in progress to change the video4linux API,
 183 this work is documented at the video4linux2 site listed below.
 184
 185
 186 9.0 --- A sample program using v4lgrabber,
 187
 188 v4lgrab is a simple image grabber that will copy a frame from the
 189 first video device, /dev/video0 to standard output in portable pixmap
 190 format (.ppm)  To produce .jpg output, you can use it like this:
 191 'v4lgrab | convert - c-qcam.jpg'
 192
 193
 194 10.0 --- Other Information
 195
 196 Use the ../../Maintainers file, particularly the  VIDEO FOR LINUX and PARALLEL
 197 PORT SUPPORT sections
 198
 199 The video4linux page:
 200   http://linuxtv.org
 201
 202 The V4L2 API spec:
 203   http://v4l2spec.bytesex.org/
 204
 205 Some web pages about the quickcams:
 206    http://www.pingouin-land.com/howto/QuickCam-HOWTO.html
 207
 208    http://www.crynwr.com/qcpc/            QuickCam Third-Party Drivers
 209    http://www.crynwr.com/qcpc/re.html     Some Reverse Engineering
 210    http://www.wirelesscouch.net/software/gqcam/   v4l client
 211    http://phobos.illtel.denver.co.us/pub/qcread/ doesn't use v4l
 212    ftp://ftp.cs.unm.edu/pub/chris/quickcam/   Has lots of drivers
 213    http://www.cs.duke.edu/~reynolds/quickcam/ Has lots of information
 214
 215