[sane-devel] [Regression][Patch] genesys: Canon Lidescan 60, head does not return

[Georg Altmann]

Hi,

after upgrading from Ubuntu 10.04 (lucid, libsane-1.0.20-13ubuntu2) to
ubuntu 12.04 (precise, libsane-1.0.22-7ubuntu1), the scan head of my
Scanner stopped returning to its starting position after each scan.

I traced the problem down in sane-backends to
commit eba438b9

    don't wait head to be parked at end of scan to improve scan speed
    - issue slow_back_home without wait flag at end of scan
    - ensure head is parked at scan start and at close
    - issue slow_back_home before doing digital processing

The problem appears to be caused by
diff --git a/backend/genesys.c b/backend/genesys.c
index f01bb6b..ecdec48 100644
--- a/backend/genesys.c
+++ b/backend/genesys.c
@@ -8029,7 +8029,7 @@ sane_cancel (SANE_Handle handle)
   /* park head if flatbed scanner */
   if (s->dev->model->is_sheetfed == SANE_FALSE)
     {
-      status = s->dev->model->cmd_set->slow_back_home (s->dev, 1);
+      status = s->dev->model->cmd_set->slow_back_home (s->dev,
s->dev->model->flags & GENESYS_FLAG_MUST_WAIT);
       if (status != SANE_STATUS_GOOD)
        {
          DBG (DBG_error,

which should probably read

      status = s->dev->model->cmd_set->slow_back_home (s->dev,
s->dev->model->flags && GENESYS_FLAG_MUST_WAIT);


The latter reproducibly fixes the problem for me.


For completeness I attached two patches:
fix-lidescan60-regression-orig-eba438b9.patch
-> Fixes the bug where it was originally introduced (commit eba438b9)

fix-lidescan60-regression-master_2012-11-19-eb9af2d4.patch
-> Fixes the bug in the current master branch (commit eb9af2d4a3)

Tested for  Canon Lidescan 60
% sane-find-scanner
[...]
found USB scanner (vendor=0x04a9 [Canon], product=0x221c [CanoScan],
chip=GL842) at libusb:002:009
[...]

% lsb_release -a
LSB Version:
core-2.0-ia32:core-2.0-noarch:core-3.0-ia32:core-3.0-noarch:core-3.1-ia32:core-3.1-noarch:core-3.2-ia32:core-3.2-noarch:core-4.0-ia32:core-4.0-noarch:cxx-3.0-ia32:cxx-3.0-noarch:cxx-3.1-ia32:cxx-3.1-noarch:cxx-3.2-ia32:cxx-3.2-noarch:cxx-4.0-ia32:cxx-4.0-noarch:desktop-3.1-ia32:desktop-3.1-noarch:desktop-3.2-ia32:desktop-3.2-noarch:desktop-4.0-ia32:desktop-4.0-noarch:graphics-2.0-ia32:graphics-2.0-noarch:graphics-3.0-ia32:graphics-3.0-noarch:graphics-3.1-ia32:graphics-3.1-noarch:graphics-3.2-ia32:graphics-3.2-noarch:graphics-4.0-ia32:graphics-4.0-noarch:printing-3.2-ia32:printing-3.2-noarch:printing-4.0-ia32:printing-4.0-noarch:qt4-3.1-ia32:qt4-3.1-noarch
Distributor ID:	Ubuntu
Description:	Ubuntu 12.04.1 LTS
Release:	12.04
Codename:	precise

% uname -a
Linux georg-ubuntu 3.2.0-29-generic-pae #46-Ubuntu SMP Fri Jul 27
17:25:43 UTC 2012 i686 i686 i386 GNU/Linux

There is also a bug report in the tracker
#313909
https://alioth.debian.org/tracker/index.php?func=detail&aid=313909&group_id=30186&atid=410366

Thank you for developing sane!

Regards,
	Georg

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