[sane-devel] Timeouts: usb_reset seems necessary to avoid bulk timeouts.

Henning Meier-Geinitz henning@meier-geinitz.de
Wed, 9 Jun 2004 22:33:11 +0200


On Wed, Jun 09, 2004 at 04:48:51PM +0100, Tom Schutzer-Weissmann wrote:
> I had problems using the Epkowa libraries (libsane-epkowa) and the
> iscan frontend with my usb scanner in kernel 2.6.
> The scanner was closed after each operation. Once closed, nothing
> could be read from it, and I got lots of BULK TIMEOUTs, although
> there were no errors when the device was reopened.
> By modifying the code so that usb_reset() was always called before
> usb_release_interface() and usb_close(), I solved the problem.

Doesn't usb_reset() cause a renumeration and therefore the device gets
a new device file? I guess this isn't the default for closing USB
devices. Maybe the usb_reset just hides a bug in the SANE backend,
libusb or the kernel.