[sane-devel] scanimage hangs at shutdown (Preparing for a sane-backends release)

Rolf Bensch rolf at bensch-online.de
Mon Aug 17 10:57:05 UTC 2015 

It's not the described bug in libusb-compat.

However, atexit() isn't working as desired in OpenSuse.

scanimage closes the usb interface from atexit() *before* sane_cancel()
is ready at the end of main().

Is this a problem of OpenSuse or should somebody rewrite the shutdown
sequence of scanimage?

Cheers,
Rolf


Am 11.08.2015 um 14:37 schrieb m. allan noah:
> Yes- this sounds like the bug in libusb-compat mentioned in my last
> email. According to the manpage for atexit, registered functions
> should be called in reverse order. So, if we can call atexit in
> scanimage, after libusb's call to atexit, that might help. You could
> try moving scanimage atexit call to after its sane_init call? I'm not
> sure that is where libusb registers, or if this is even a valid
> long-term solution, but it is worth a try.
> 
> allan
> 
> On Tue, Aug 11, 2015 at 6:42 AM, Rolf Bensch <rolf at bensch-online.de> wrote:
>> Hi Allan,
>>
>> I compared scanimage and xsane logs, and I found a difference after
>> "Reader task terminated".
>>
>> It seems that scanimage has a problem closing the scanner.
>>
>> I removed scanned data in the log files for better reading.
>>
>> Hope this helps.
>>
>> Cheers,
>> Rolf
>>
>>
>>
>> Am 08.08.2015 um 00:29 schrieb m. allan noah:
>>> After a bit of searching, this looks like a bug in libusb-compat:
>>> http://sourceforge.net/p/libusbx/mailman/libusbx-devel/thread/522AF646.7060108@redhat.com/
>>>
>>> allan
>>>
>>> On Fri, Aug 7, 2015 at 6:21 PM, m. allan noah <kitno455 at gmail.com> wrote:
>>>> Rolf- can you get a log of the scanimage and xsane shutdown sequences,
>>>> and see if they call something in a different order? I had one report
>>>> of this same error with the Fujitsu iX500, but I never reproduced.
>>>>
>>>> allan
>>>>
>>>> On Fri, Aug 7, 2015 at 5:40 PM, Rolf Bensch <rolf at bensch-online.de> wrote:
>>>>> Hello,
>>>>>
>>>>> I just fixed an usb communication problem with OpenSuse and the Pixma
>>>>> backend.
>>>>>
>>>>> Scanning with xsane is working with my CS9000F scanner. But if I'm
>>>>> scanning with scanimage, I always get this message at the end of each scan:
>>>>> "libusb: warning [libusb_close] internal signalling read failed, closing
>>>>> anyway"
>>>>>
>>>>> Then I need to terminate scanimage with 2x CTRL C. And sometimes the USB
>>>>> bus is blocked for my scanner until I reboot the machine. The scanned
>>>>> image is OK.
>>>>>
>>>>> I'm testing OpenSuse 13.2 in VirtualBox 5.0 on Ubuntu 14.04.1, both x86_64.
>>>>>
>>>>> Maybe you can give me a hint where to look to fix this issue or Allan
>>>>> can fix this for me. I'm not very familiar with the usb library.
>>>>>
>>>>> Many thanks for your help.
>>>>>
>>>>> Cheers,
>>>>> Rolf
>>>>>
>>>>> Am 04.08.2015 um 13:11 schrieb Johannes Meixner:
>>>>>>
>>>>>> Hello,
>>>>>>
>>>>>> On Aug 3 14:08 m. allan noah wrote (excerpt):
>>>>>>> ... I know that Gentoo has some systemd compilation fixes.
>>>>>>
>>>>>> Everey Linux distribution should submit their patches to SANE
>>>>>> upstream (provided their changes make sense for upstream).
>>>>>>
>>>>>> Here our (i.e. openSUSE) patches that we still have:
>>>>>>
>>>>>>
>>>>>> 1)
>>>>>> Right now I filed
>>>>>> https://alioth.debian.org/tracker/index.php?group_id=30186&atid=410366
>>>>>> with my fix-buffer-overflow.patch attached
>>>>>> that fixes a too small array in backend/niash.c
>>>>>>
>>>>>>
>>>>>> 2)
>>>>>> My re-add-SANE_CAP_ALWAYS_SETTABLE.patch re-adds SANE_CAP_ALWAYS_SETTABLE
>>>>>> to sane.h which was erroneously removed in sane-backends-1.0.20 so that
>>>>>> sane-frontends and xsane can no longer build, see
>>>>>> http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=527675
>>>>>>
>>>>>> re-add-SANE_CAP_ALWAYS_SETTABLE.patch
>>>>>> -----------------------------------------------------------------------------
>>>>>>
>>>>>> --- include/sane/sane.h.orig    2009-06-12 10:19:19.000000000 +0200
>>>>>> +++ include/sane/sane.h 2009-06-12 10:20:12.000000000 +0200
>>>>>> @@ -115,6 +115,7 @@ SANE_Device;
>>>>>>  #define SANE_CAP_AUTOMATIC             (1 << 4)
>>>>>>  #define SANE_CAP_INACTIVE              (1 << 5)
>>>>>>  #define SANE_CAP_ADVANCED              (1 << 6)
>>>>>> +#define SANE_CAP_ALWAYS_SETTABLE       (1 << 7)
>>>>>>
>>>>>>  #define SANE_OPTION_IS_ACTIVE(cap)     (((cap) & SANE_CAP_INACTIVE)
>>>>>> == 0)
>>>>>>  #define SANE_OPTION_IS_SETTABLE(cap)   (((cap) &
>>>>>> SANE_CAP_SOFT_SELECT) != 0)
>>>>>> -----------------------------------------------------------------------------
>>>>>>
>>>>>>
>>>>>> The re-add-SANE_CAP_ALWAYS_SETTABLE.patch still applies for
>>>>>> current sane-backends-git20150804.tar.gz so that I assume
>>>>>> SANE_CAP_ALWAYS_SETTABLE is still missing in sane-backends.
>>>>>>
>>>>>> I did not verify whether or not meanwhile all SANE frontends
>>>>>> also no longer use SANE_CAP_ALWAYS_SETTABLE so that it could
>>>>>> meanwhile be really removed in sane-backends.
>>>>>>
>>>>>>
>>>>>> 3)
>>>>>> My fix-mustek_pp_ccd300.c.patch fixes undefined 'foo = ++foo modulo bar'
>>>>>> operations in mustek_pp_ccd300.c see
>>>>>> https://bugzilla.opensuse.org/show_bug.cgi?id=498435
>>>>>> and
>>>>>> https://alioth.debian.org/tracker/index.php?func=detail&aid=311857&group_id=30186&atid=410366
>>>>>> where the upstream maintainer did not understand what is wrong and
>>>>>> closed it  as "Wont Fix" so that we must keep this patch forever
>>>>>> to make at least the code somehow valid for the compiler.
>>>>>> fix-mustek_pp_ccd300.c.patch is attached to the above
>>>>>> alioth.debian.org bug tracker issue.
>>>>>> Of course because the result of 'foo = ++foo' is undefined
>>>>>> I cannot know if my patch implements what is actually intended.
>>>>>> My patch implements an arbitrary result that only makes the
>>>>>> compiler happy.
>>>>>>
>>>>>>
>>>>>> 4)
>>>>>> My install-umax_pp-tool.patch installs tools/umax_pp as /usr/bin/umax_pp
>>>>>> which is built but not installed but it is needed to recover from
>>>>>> a failed scan with scanners which use the umax_pp backend, see
>>>>>> http://bugs.debian.org/496833
>>>>>>
>>>>>> install-umax_pp-tool.patch
>>>>>> --------------------------------------------------------------------
>>>>>> --- tools/Makefile.am.orig      2009-02-20 17:51:09.000000000 +0100
>>>>>> +++ tools/Makefile.am   2009-06-05 15:08:45.000000000 +0200
>>>>>> @@ -7,8 +7,8 @@
>>>>>>  AM_CPPFLAGS = -I. -I$(srcdir) -I$(top_builddir)/include \
>>>>>>   -I$(top_srcdir)/include
>>>>>>
>>>>>> -bin_PROGRAMS = sane-find-scanner gamma4scanimage
>>>>>> -noinst_PROGRAMS = sane-desc umax_pp
>>>>>> +bin_PROGRAMS = sane-find-scanner gamma4scanimage umax_pp
>>>>>> +noinst_PROGRAMS = sane-desc
>>>>>>
>>>>>>  if CROSS_COMPILING
>>>>>>  HOTPLUG =
>>>>>> --------------------------------------------------------------------
>>>>>>
>>>>>> The install-umax_pp-tool.patch still applies for current
>>>>>> sane-backends-git20150804.tar.gz so that I assume
>>>>>> tools/umax_pp is still not installed by default.
>>>>>>
>>>>>>
>>>>>>
>>>>>> In general regarding parallel port scanner drivers:
>>>>>>
>>>>>> The above issues 3) and 4) are about parallel port scanner drivers.
>>>>>>
>>>>>> I wonder if support for parallel port scanners is still needed?
>>>>>>
>>>>>> I assume that basically nobody tests parallel port scanners.
>>>>>> Probably also basically nobody usues parallel port scanners.
>>>>>>
>>>>>> In this case parallel port scanner drivers should be dropped
>>>>>> because in practice they are no longer maintained.
>>>>>>
>>>>>> As a first step parallel port scanner drivers could be
>>>>>> no longer built by default e.g. via something like
>>>>>>   configure --without-parport
>>>>>> by default.
>>>>>>
>>>>>>
>>>>>> Kind Regards
>>>>>> Johannes Meixner
>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> "well, I stand up next to a mountain- and I chop it down with the edge
>>>> of my hand"
>>>
>>>
>>>
>>
> 
> 
>

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