[sane-devel] regression in sane-backends 1.0.25, AGFA Snapscan 1212U_2 not found

m. allan noah kitno455 at gmail.com
Mon Nov 16 00:16:06 UTC 2015

It looks like there were no changes to the snapscan backend between
1.0.24 and 1.0.25, other than some minor typo changes. This implies
that the difference is in our USB changes made to work around Linux
kernel USB problems. Specifically, these:

commit 014b45d920f1fb630e1a31bb01f1da02ea2a6a87
Author: m. allan noah <kitno455 at gmail.com>
Date:   Tue Dec 16 10:23:55 2014 -0500

    sanei_usb: Linux USB3/xhci workarounds

    add calls to sanei_usb_set_altinterface in sanei_usb_close and
    sanei_usb_clear_halt- hopefully work around USB3/xhci problems
    in Linux. Also, remove some unused code, and fix debug messages.

commit 365b619dfe4ec49045d00dcda973ffa811599e80
Author: Olaf Meeuwissen <olaf.meeuwissen at avasys.jp>
Date:   Tue Dec 2 11:59:35 2014 +0900

    Set USB configuration only if different from the current one

    This follows up on earlier USB3 fixes.  It only addresses libusb-1.0
    because there is no convenience API for libusb-0.1 to get the current

commit 5283a8792e8694596a9865c3e58c4f9f307ce38b
Author: Olaf Meeuwissen <olaf.meeuwissen at avasys.jp>
Date:   Tue Dec 2 11:37:25 2014 +0900

    Fix memory leak w/ libusb-1.0 (introduced in 71c1a00)

commit 71c1a0068fdb0273883096451db2bf1a0e7f4d2c
Author: Olaf Meeuwissen <olaf.meeuwissen at avasys.jp>
Date:   Tue Dec 2 10:03:38 2014 +0900

    Set USB configuration only if there are alternative ones

    This fixes USB3 issues for the epson and epson2 backends.  Both these
    backends already made sure to send an even number of reads and writes
    but were affected nevertheless.

    It also solves USB3 issues with the third party epkowa backend.  This
    one doesn't bother to ensure even counts of packets read and written.
    It works fine when this fix is applied (and it no longer clears halts
    w/o a stall condition).  Note, there is no need to ensure even packet

We would need to compile sane-backends from source, removing some or
all of these commits, to find the culprit. Is this something you can


On Sun, Nov 15, 2015 at 12:07 PM, Olaf Hering <olaf at aepfle.de> wrote:
> See https://bugzilla.suse.com/show_bug.cgi?id=955079
> Since the upgrade to sane-backends-1.0.25 my AGFA Snapscan 1212U_2 is
> found only once after its plugged in. If I revert to the previous 1.0.24
> package state scanning works fine again.
> Any idea how to fix it?
> Olaf
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