[Preston] Re: USB support under Linux

[Adrian Hodgson]

Guy wrote:
> Hi Adrian,
> Last night we were talking about USB support for devices under Linux.
> A useful place to start is:
> http://www.linux-usb.org/
> There, there is a list of manufacturer/device ID numbers and a useful tool in 
> the form of a program called 'usbview'. This program shows you the 
> connections on your USB port and you can find the ID numbers.
> When you have found these ID numbers you can try to track down a relevant 
> module that drives the device.
> 
> The command 'lsmod' lists all the modules that are loaded into your kernel 
> (you have to be root and on redhat based systems you may have to type 
> '/sbin/lsmod' i.e. give the full path to the command). Try running lsmod, 
> plugging in your usb device and running lsmod again to see if anything has 
> changed. The kernel has a database of ID numbers and associated modules to 
> load when it detects the presence of a device. If the kernel doesn't load a 
> module when you plug in a device  it doesn't always mean the device is 
> unsupported! Maybe the device has not been added to the database and the 
> module for another similar device might work.
> 
> The commands 'insmod' and 'modprobe' are useful for adding modules to the 
> running kernel (insmod inserts a module, modprobe is similar but also loads 
> other modules that the one in question depends on.) The program  'modconf' 
> has a graphical interface for selecting modules to load.
> 
> http://www.google.com/linux
> is a good search engine for Linux related stuff
> 
> Check what kernel you are running - the 2.4.xx series has much better USB 
> support than the 2.2.xx (type 'uname -a')
> 
> I have to say that support for webcams and scanners is patchy under Linux. 
> The only piece of hardware I own that doesn't work (yet) under Linux is a 
> webcam (I have never owned a scanner).
> 
> There is a feature on scanner support in the new 'Linux Format' magazine.
> 
> Good Luck!

Guy hope you  do not mind me replying direct as well as via the group, 
and trying to pick your brains but here goes anyway.  It does look to me 
as though the Kernal is recognising something.  But gtkam will not 
access the camera?

Without the USB web cam connected then lsmod reports this :-

module		size		used by		Not tainted
sb		9024		0	(autoclean)
sb-lib		39520		0	(autoclean)(sb)
uart401		7680		0	(autoclean)(sb_lib)
sound		69516		0	(autoclean)(sb_libuart401)
soundcore	6244		4	(autoclean)(sb_lib sound)
autofs		11044		0	(autoclean)(unused)
ne		7904		1	
8390		7876		0	[ne]
ipchains	39464		4	
ide-cd		30432		0	(autoclean)
cdrom		32032		0	(autoclean)[ide-cd]
usb-uhci	24324		0	(unused)
usbcore		71200		1	[usb-uhci]
ext3		64992		2	
jbd		47220		2	[ext3]




Then I connect the usb camera and wait a few seconds the try again. 
This time lsmod reports :-

module		size		used by		Not tainted
stv680		24736		0	(unused)
videodev	7712		1	[stv680]
sb		9024		0	(autoclean)
sb-lib		39520		0	(autoclean)(sb)
uart401		7680		0	(autoclean)(sb_lib)
sound		69516		0	(autoclean)(sb_libuart401)
soundcore	6244		4	(autoclean)(sb_lib sound)
autofs		11044		0	(autoclean)(unused)
ne		7904		1	
8390		7876		0	[ne]
ipchains	39464		4	
ide-cd		30432		0	(autoclean)
cdrom		32032		0	(autoclean)[ide-cd]
usb-uhci	24324		0	(unused)
usbcore		71200		1	[stv680 usb-uhci]
ext3		64992		2	
jbd		47220		2	[ext3]


It does look to me as though the camera is being recognised as and 
stv680 and the kernal is loading something!

When I run gtkam and look for the camera  find a STV0680  I can select 
this but the response is always "unable to initialise camera"

I may well be missing something and I admit to not understanding much of 
this linux system but if you can help and tell me where things are going 
wrong then it would be much appreciated.


Cheers Adrian