[sane-devel] Re: [Linux-usb-users] Problems with HP 6200C scanner and SANE

[Alan Stern]

On Sat, 12 Jun 2004, David Härdeman wrote:

> On Mon, May 31, 2004 at 02:58:12PM -0400, Alan Stern wrote:
> >On Mon, 31 May 2004, David Härdeman wrote:
> >> I'm currently trying to get an HP 6200C USB scanner to work with SANE 
> >> (1.0.14) under Linux (Debian woody with some backports, kernel 2.4.26). 
> >> Whenever I scan something which requires a low amount of data (lineart 
> >> picture at 100dpi for instance), everything works just fine. But when I 
> >> scan a more bandwidth hungry pic, it never succeeds. I've tried this 
> >> both with the "scanner" module in the kernel and with libusb but both 
> >> seem to experience the same problems.
> >> 
> >> I have tried sane's "dumb-read" option and all other option which were 
> >> mentioned in the sane-hp man page but I'm running out of ideas. Any 
> >> clues what might cause this (might later kernels be too picky with their 
> >> timing requirements)?
> >
> >The most likely explanation is that some other program (possibly a hotplug 
> >utility) is trying to access the scanner while you're using it, thereby 
> >confusing the scanner and causing it to fail.  I've seen reports from 
> >other people where the "usbmodules" program did this.  See what happens if 
> >you turn off all hotplug support.
> 
> Hi,
> and sorry for the delay in answering.
> 
> I am running this on Debian Woody (with backported usblib and sane 
> packages of recent versions), so there is no hotplug support on the 
> system, the only other thing I could think of is the "nut" UPS daemon 
> which checks the status of the UPS over USB.
> 
> However, disabling nut and trying to scan did not help sort out the 
> problem.
> 
> Any other suggestions?

Nothing much about 2.4.26 springs to mind.  You might try turning on USB 
debugging in the kernel configuration to see if the system log contains 
any useful information when the fault occurs.

Or you could try moving up to Linux 2.6, which has a more robust USB 
stack.

Alan Stern