6. Troubleshooting

6.1. Help, How do I figure out what my USB camera chipset is if the model isn't listed in your HOWTO?

If you have a usb camera (and /proc filesystem support and usb-filesystem support), issue the following at the command line:

$ cat /proc/bus/usb/devices

You should receive output including (but not necessarily limited to) the following:

T: Bus=01 Lev=01 Prnt=01 Port=01 Cnt=01 Dev#= 3 Spd=12 MxCh= 0 D: Ver= 1.01 Cls=ff(vend.) Sub=ff Prot=ff MxPS= 8 #Cfgs= 1 P: Vendor=0545 ProdID=8080 Rev= 3.0a S: Product=USB IMAGING DEVICE

The line beginning "T:" is the USB bus the device is attached to. The "P:" indicates (obviously) the vendor and product ID, which are catalogued at the linux USB Project homepage.

6.2. Help, I can't find the camera device in /dev!

Assuming your connection type is supported, and your camera is working, see Section 3.2.

6.3. Help, I can see the camera device, but I can't access it!

See Section 3.3.

6.4. Help, my camera has a driver that is source-only, i.e., has to be built by me! Where do I start?

First, check if your Linux distribution offers a pre-compiled binary of the driver. If that is not the case, be sure you have kernel sources installed. You will also need at a minimum GNU make, gcc, binutils and perhaps other programs installed depending on your distribution. Download the driver source (in this example named src.tar.gz) and uncompress/untar it:

$ tar -xvzf src.tar.gz

Then, change to the directory of your kernel source:

# cd /usr/src/linux

Make the necessary source files:

# make oldconfig # make dep

Now, change to the directory where you unpacked the driver source and read the README and/or INSTALL files for instructions on how to make the driver. Usually this involves some combination of "make" "make all" and/or "make install." Assuming it compiles correctly, you can simply load the new module with modprobe. If you have any problems, see Section 6.6.

6.5. Help, my camera is supported by a driver that has to be patched into my kernel! What do I do?

See the section on patching of the Kernel-HOWTO at The Linux Documentation Project.

The short and unguaranteed version of patching, by your humble author, goes as follows: Be sure you have the same prerequisites outlined in Section 6.4 installed. First, on the command line or in an xterm change to the source directory of the kernel version you are (or will be) running with the camera patch (in this example named patch.diff).

# cd /usr/src/linux # patch -p1 -E patch.diff

You should see a confirmation that the 'hunks' were successfully applied. At this point, you can make menuconfig or whatever program you use to recompile, enabling the appropriate support. If any of the hunks failed, or you run into any problems in addition to the link referenced above you, should consult man patch and Section 6.6.

6.6. Help--as in, where can I get more of it?

See the video4linux mailing list headquarters at https://listman.redhat.com/mailman/listinfo/video4linux-list.

6.7. Help, I want to contribute to Video4Linux support in Linux! Who do I get in touch with?

See this page.