[sane-devel] fujitsu (avision) scanner not being found after some time

[m. allan noah]

Some scanners go to sleep, and cannot wake up using SANE. This is
because they shut down USB endpoint 0 to save power. This is in
violation of the USB spec. This does not present a problem on windows,
because the driver stays running, and so does not use endpoint 0 after
the driver starts. We use endpoint 0 every time we open the device.
The Fujitsu fi-6670 has this problem, for instance.

I am not sure this is your problem here, but it sounds like it.

Perhaps you should stop changing the power-save-time option, and see
if that helps?

allan

On Fri, Nov 16, 2012 at 11:04 AM, dabicho <tsukebumi at gmail.com> wrote:
> Hello.
> I am working on a system with a function to scan documents.
> When this option is selected, a new process is started to look, open and
> configure a scanner and scan the documents.
> However after some time, sane_find_scanner takes a long time to return and
> finds nothing.
> It is needed to turn on and off the scanner or unplug and plug again the usb
> cable.
>
> Why is this happening?
> Is there any way I can workaround this in software?
>
> As part of the scanner configuration, I am doing
>
> sane_control_option(saneH, powerSaveTimeOpt, SANE_ACTION_SET_VALUE,
> &powerTime, &rVal);
>
> where powerSaveTimeOpt has the correct value as returned by
> sane_get_option_descriptor(saneH, j); // name is "power-save-time"
> and powerTime has a value of 0
> As I found that was an issue with another avision scanner. But this is not
> working this time.
>
> The scanner is
> device `avision:libusb:001:012' is a Fujitsu fi-5015C flatbed scanner
> Sane backends are
> 1.0.22
>
> Thank you for any light you can shed into this.
>
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