[sane-devel] 44-10 vs epson 1250

[Henning Meier-Geinitz]

Hi,

On Fri, Oct 18, 2002 at 05:25:44PM +0200, Till Kamppeter wrote:
> When I have only an Epson Perfection 1260 connected ("plustek" driver) 
> the "snapscan" backend takes around 15 seconds, with "snapscan" 
> commented out xsnae needs less than 10 seconds to start, with "snapscan" 
> around 25. "mustek-usb" is on the second place with something like two 
> seconds.

The USB detection funtion in sanei_usb isn't very effective.
For every sanei_usb_attach_matching_devices it checks all the
/dev/usb/scanner devices, opens them, sends the vendor/product id
ioctls and closes them. That's done for every scanner in the backend.
For a scanimage -L, about 1300 files are opened.

However, the real culprit seems to be the USB scanner driver:

Times for scanimage -L on my system with to Mustek USB scanners
attached:

* without scanner driver (with libusb):            0.437s
* with the scanner driver from Linux 2.4.20pre10: 19.385s

Now I'm using a patched kernel scanner driver that disables the
warning messages sent to syslog, fixes the "unable-to-rmmod" bug and
adds support for devices without bulk-out-endpoints:

* 0.437s

That's not a joke. I don't know which of the changes makes the
difference, but it works (and the annoying messages in syslog are
gone). The patch is from Sergey Vlasov and was already submitted to
the maintainer of the USB scanner module and the linux-usb-devel
mailinglist. They don't seem to be very interested until now, however.

Bye,
  Henning




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