[sane-devel] Problems with USB 2.0 / ehci_hcd / Snapscan backend

[Wolfram Heider]

Am Montag, 7. Februar 2005 19:47 schrieb Oliver Schwartz:
> Hi all,
>
> I got a problem report from someone trying to use an Epson Perfection
> 1670 on an USB 2.0 port using ehci_hcd+ohci_hcd as kernel drivers.
> After firmware upload the scanner stops sending data for some reason
>
> If ehci_hcd is not loaded during boot (only ohci_hcd is still loaded)
> the scanner works just fine.
>
> My own scanner is only USB 1.1 and my PC doesn't have a USB 2.0 port
> either, but even connected to an USB 2.0 Powerbook it will still be
> handled by ohci_hcd, so I cannot reproduce this problem here.
>
> My questions now are:
>
> - Has anybody else seen any problems with ehci_hcd and USB 2.0
> scanners, or is this particular for the Epson family handled by the
> Snapscan backend?
>
> - Can anybody with an Epson Perfection 660 / Perfection 2480 /
> Perfection 2580 confirm those problems?
>
> - Can anybody with a newer Benq model that uses USB 2.0 confirm these
> problems?
>
> Happy testing,
>
> Oliver

Hello Oliver,

on machines of friends I got an epson perfection 660  working flawlessly as 
well as an epson perfection 1670 and it made no difference if USB 1.1 or 2.0. 
But on my own box running under SuSE 9.1 (kernel 2.6.5 - 7.111) I faced 
problems with some other USB 2.0 devices (USB-stick, USB-hub) connected to an 
USB 1.1 port which didn't appear on identical configurated boxes with USB 2.0 
ports. "modprobe ohci" ended in an endless loop. My impression is that there 
must be something wrong with the USB downward compability. Having installed 
an USB 2.0-card and so excluded each USB-driver from being loaded except the 
ohci everything works fine. I don't know if this may be of any help for you 
but perhaps it has to say something.

Greetings

Wolfram Heider