What Distro to use::USB

[Kevin Buettner]

On Nov 14, 11:43pm, Michael Alexander Green wrote:

> Which scanner are you using? How did you setup your scanner for USB? Which
> config files did you change? What was the syntax you used? Thanks.

Trent Shipley was also interested in these details, asking me for my
"USB tail of woe." I had meant to reply sooner, but was busy at the
time...

I have an HP ScanJet 6250Cxi.

As mentioned in my previous mail, it was connected to my computer via
the SCSI interface.  I was seeing SCSI timeouts which were preventing
the scanner from operating reliably, so I decided to give USB a try.
I still don't have an explanation for the SCSI timeouts.

It is my understanding that the kernel version that you are using
makes a big difference when attempting to use USB.  I'm running
2.4.0-test10.  When configuring this kernel, you need to enable
some of the USB options.  I have the following enabled:

    CONFIG_USB=m
    CONFIG_USB_DEBUG=y
    CONFIG_USB_DEVICEFS=y
    CONFIG_USB_UHCI=m
    CONFIG_USB_SCANNER=m
    CONFIG_USB_PRINTER=m
    CONFIG_USB_HID=m
    CONFIG_USB_KBD=m
    CONFIG_USB_MOUSE=m

I can probably do without the last four, but I enabled them so that I
could experiment a bit if I get any more USB devices.

I have the following lines for usb and my scanner in modules.conf:

    alias usb-controller usb-uhci
    post-install usb-uhci modprobe scanner

I'd really prefer not to have the last line.  It is my understanding
that you can do without this line if you use "policy scripts" and
possibly a usb daemon.  I need to do more investigation regarding
these facilities.

There is a directory /proc/bus/usb.  This needs to be mounted in order
for you to be able to make use of the devices in /dev/usb.  Either
do

    mount -t usbdevfs usbdevfs /proc/bus/usb

or put the appropriate line in your /etc/fstab.  RH7 runs this command
for you in rc.sysinit.

Finally, you'll need to change the configuration file that SANE
uses to find your scanner.  I have the following two lines in
/etc/sane.d/hp.conf:

    /dev/usb/scanner0
    option connect-device

....

With regard to the tail of woe that Trent Shipley asked for, probably
the biggest problem I had was that I didn't power cycle my scanner
in between asking it to be a SCSI device and being a USB device.  I
spent a lot of time fiddling with options, rebooting my system, etc.
when all I would've had to do would be to unplug the scanner, wait a
few seconds, and then plug it in again.

Another problem was that although I do have USB ports on my computer,
I didn't realize that I had to enable them in the BIOS.

I would estimate that 75% of the time that it took for me to set up
USB was "wasted" on these two problems.

....

The following URL is very helpful:

    http://www.linux-usb.org/

I also read many of the files in Documentation/usb (in the kernel
sources).  In particular, the file scanner-hp-sane.txt describes the
layout of the configuration lines in hp.conf.  Also, proc_usb_info.txt
describes the USB filesystem mounted at /proc/bus/usb.

Kevin