[sane-devel] Scanning produces black images

Gerard Klaver gerard at gkall.hobby.nl
Mon Apr 16 08:38:35 UTC 2007


On Mon, 2007-04-16 at 07:50 +0200, Gerhard Jaeger wrote:
> On Sonntag, 15. April 2007, JKD wrote:
> > El Sun, 15 de Apr de 2007, a las 09:58:08PM +0200, Magnus Rosenbaum dijo:
> > > I upgraded my Linux kernel from 2.6.18 to 2.6.19 and noticed a strange
> > > behaviour in xsane and also in kooka: The program acts als it would
> > > normally scan, but the scanner does not do anything and the result is a
> > > completely black image.
> > > 
> > > However scanning with scanimage works allright!
> > > 
> > > The behaviour is reproducible with kernel 2.6.19 and also 2.6.21-rc5. When
> > > I boot 2.6.18 scanning works as expected again.
> > > 
> > > Does anyone have an idea, how I could further investigate this problem?
> > 
> > Some days ago a user reported the same issue. For some unknown reason,
> > with newer kernels some backends are experiencing problems, retrieving a
> > black image from scanner. This is my experience about this issue with
> > hp3900 backend:
> [SNIPSNAP]
> >
> > I don't really know what the real problem is. Perhaps backends must be
> > compiled against current library or kernel versions. Once compiled,
> > problem is fixed.
> 
> This is also an issue with the Plustek backend, reported by various
> Ubuntu and Gentoo users. As already stated by PhobosK, the problem is
> the kernel option CONFIG_USB_SUSPEND. This in deed is needed for laptop
> users. It is currently marked as "experimental" but already used by various
> distros. 
> 
> I think the problem really is, that libusb does not know anything about that
> suspend stuff and therefore we have more or less no possibility to wakeup
> the port, where the scanner is connected to.
> One thing that could be observed: In all cases, scanimage works fine - guess
> this is because it never closes the port until the scan process is done.
> 
> Any ideas around?
> 
> Gerhard
> 
> 
> 
> 
Update of libusb.h/.c and sanei_usb.h/.c?, not seen IIRC any email about
it on the libusb mailing list yet. 
-- 
--------
m.vr.gr.
Gerard Klaver





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