[sane-devel] Bad Performance uhci (vs. usb-ohci ,ohci)

[Bertrik Sikken]

Hi,

Gunther Mayer wrote:
> the "uhci" module suffers from very bad performance (linux-2.4.17).
> 
> Scanning 150dpi A4 (merlin670 for Canon N670U over libusb-0.1.4) gives:
>   uhci:    135 sec.
>   usb-uhci: 43 sec.
>   ohci:     35 sec
> 
> This corresponds to about 50K/sec for 'uhci' (and the scanner must stop'n'start) !
> 
> Is this a known bug in "uhci" ?

I found something similar, with transfer rates below 100 kB/s
while it was something like 700 kB/s before, resulting in
heavy backtracking of the scanner head of my HP3300 scanner.
I too used (a custom compiled) kernel 2.4.17, libusb 0.1.4 and
uhci (compiled as module). Using the usb-uhci module instead of
the uhci module solved it for me. I did not further research the
issue, so I can't really tell for sure what caused the problem.

Regards,
Bertrik Sikken