1c-qcam - Connectix Color QuickCam video4linux kernel driver 2 3Copyright (C) 1999 Dave Forrest <drf5n@virginia.edu> 4 released under GNU GPL. 5 61999-12-08 Dave Forrest, written with kernel version 2.2.12 in mind 7 8 9Table of Contents 10 111.0 Introduction 122.0 Compilation, Installation, and Configuration 133.0 Troubleshooting 144.0 Future Work / current work arounds 159.0 Sample Program, v4lgrab 1610.0 Other Information 17 18 191.0 Introduction 20 21 The file ../../drivers/media/video/c-qcam.c is a device driver for 22the Logitech (nee Connectix) parallel port interface color CCD camera. 23This is a fairly inexpensive device for capturing images. Logitech 24does not currently provide information for developers, but many people 25have engineered several solutions for non-Microsoft use of the Color 26Quickcam. 27 281.1 Motivation 29 30 I spent a number of hours trying to get my camera to work, and I 31hope this document saves you some time. My camera will not work with 32the 2.2.13 kernel as distributed, but with a few patches to the 33module, I was able to grab some frames. See 4.0, Future Work. 34 35 36 372.0 Compilation, Installation, and Configuration 38 39 The c-qcam depends on parallel port support, video4linux, and the 40Color Quickcam. It is also nice to have the parallel port readback 41support enabled. I enabled these as modules during the kernel 42configuration. 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. 51To 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 59But that is my personal preference. 60 612.2 Configuration 62 63 The configuration requires module configuration and device 64configuration. I like kmod or kerneld process with the 65/etc/modprobe.conf file so the modules can automatically load/unload as 66they are used. The video devices could already exist, be generated 67using MAKEDEV, or need to be created. The following sections detail 68these procedures. 69 70 712.1 Module Configuration 72 73 Using modules requires a bit of work to install and pass the 74parameters. 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 81will cause the kmod/modprobe to do certain things. If you are 82using kmod, then a request for a 'char-major-81-0' will cause 83the 'c-qcam' module to load. If you have other video sources with 84modules, you might want to assign the different minor numbers to 85different modules. 86 872.2 Device Configuration 88 89 At this point, we need to ensure that the device files exist. 90Video4linux used the /dev/video* files, and we want to attach the 91Quickcam to one of these. 92 93 ls -lad /dev/video* # should produce a list of the video devices 94 95If 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 106your 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 112special character files with the right major and minor numbers. All 113of the special device files are listed in ../devices.txt. If you 114would like the c-qcam readable by non-root users, you will need to 115change the permissions. 116 1173.0 Troubleshooting 118 119 If the sample program below, v4lgrab, gives you output then 120everything 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 127system (CONFIG_PROC_FS), the parallel printer support 128(CONFIG_PRINTER), the IEEE 1284 system,(CONFIG_PRINTER_READBACK), you 129should 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 134Returns: 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 140and well. A common problem is that the current driver does not 141reliably detect a c-qcam, even though one is attached. In this case, 142 143 modprobe -v c-qcam 144or 145 insmod -v c-qcam 146 147 Returns a message saying "Device or resource busy" Development is 148currently underway, but a workaround is to patch the module to skip 149the detection code and attach to a defined port. Check the 150video4linux mailing list and archive for more current information. 151 1523.1 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 1714.0 Future Work / current workarounds 172 173 It is hoped that this section will soon become obsolete, but if it 174isn't, you might try patching the c-qcam module to add a parport=xxx 175option as in the bw-qcam module so you can specify the parallel port: 176 177 insmod -v c-qcam parport=0 178 179And bypass the detection code, see ../../drivers/char/c-qcam.c and 180look for the 'qc_detect' code and call. 181 182 Note that there is work in progress to change the video4linux API, 183this work is documented at the video4linux2 site listed below. 184 185 1869.0 --- A sample program using v4lgrabber, 187 188v4lgrab is a simple image grabber that will copy a frame from the 189first video device, /dev/video0 to standard output in portable pixmap 190format (.ppm) To produce .jpg output, you can use it like this: 191'v4lgrab | convert - c-qcam.jpg' 192 193 19410.0 --- Other Information 195 196Use the ../../Maintainers file, particularly the VIDEO FOR LINUX and PARALLEL 197PORT SUPPORT sections 198 199The video4linux page: 200 http://linuxtv.org 201 202The V4L2 API spec: 203 http://v4l2spec.bytesex.org/ 204 205Some 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 214 215 216
