1sane-scsi(5)             SANE Scanner Access Now Easy             sane-scsi(5)
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NAME

6       sane-scsi - SCSI adapter tips for scanners
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DESCRIPTION

9       This  manual  page  contains various operating-system specific tips and
10       tricks on how to get scanners with a SCSI interface working.
11

GENERAL INFO

13       For scanners with a SCSI interface, it may be  necessary  to  edit  the
14       appropriate  backend configuration file before using SANE for the first
15       time.  For most systems, the configuration file should list the name of
16       the  generic  SCSI device that the scanner is connected to (e.g., under
17       Linux, /dev/sg4 or /dev/sge is such a generic SCSI device).  It is cus‐
18       tomary to create a symlink from /dev/scanner to the generic SCSI device
19       that the scanner is connected to.  In this case, the configuration file
20       simply lists the line /dev/scanner.  For a detailed description of each
21       backend's configuration file, please refer to the relevant backend man‐
22       ual  page  (e.g.,  sane-epson(5)  for Epson scanners, sane-hp(5) for HP
23       scanners, etc.).
24
25       For some operating systems (e.g. Linux and OS/2), there is an alternate
26       way  of specifying scanner devices.  This alternate way allows to iden‐
27       tify scanners by the SCSI vendor and model string and/or  by  the  SCSI
28       device address (consisting of bus number, channel number, id, and logi‐
29       cal unit number).  The syntax for specifying a scanner in this way is:
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31              scsi VENDOR MODEL TYPE BUS CHANNEL ID LUN
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33       where VENDOR is the SCSI vendor string, MODEL is the SCSI model string,
34       TYPE is type SCSI device type string, BUS is the SCSI bus number (named
35       "host" in /proc/scsi/scsi), CHANNEL is the SCSI channel number,  ID  is
36       the  SCSI id, and LUN is the logical unit number of the scanner device.
37       The first two fields are strings which  must  be  enclosed  in  double-
38       quotes  if  they contain any whitespace.  The remaining four fields are
39       non-negative integer numbers.  The correct values for these fields  can
40       be  found  by  using operating system specific tools, e.g. for Linux by
41       looking at the output of the command "cat  /proc/scsi/scsi".   To  sim‐
42       plify  configuration,  a field's value can be replaced with an asterisk
43       symbol (``*'').  An asterisk has the effect that any value  is  allowed
44       for  that  particular  field.   This  can have the effect that a single
45       scsi-line matches multiple devices.  When this happens,  each  matching
46       device  will  be probed by the backend one by one and registered if the
47       backend thinks it is a compatible device.  For example, the line
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49              scsi MUSTEK MFS-06000CX Scanner 0 00 03 00
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51       would attach the Mustek SCSI scanner with the following /proc/scsi/scsi
52       entry:
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54         Host: scsi0 Channel: 00 Id: 03 Lun: 00
55           Vendor: MUSTEK   Model: MFS-06000CX Rev: 4.04
56           Type:   Scanner  ANSI SCSI revision: 0
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58       Usually  it's  sufficient  to use vendor and model strings only or even
59       only the vendor string. The following example
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61              scsi MUSTEK * * * * * *
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63       would have the effect that all SCSI devices in the system with a vendor
64       string of MUSTEK would be probed and recognized by the backend.
65
66       If  the  remainder  of  a  scsi-string  consists of asterisks only, the
67       asterisks can be omitted.  For example, the following line  is  equiva‐
68       lent to the one specified previously:
69
70              scsi MUSTEK
71
72       On  some  platforms  (e.g., OpenStep), SANE device names take a special
73       form.  This is explained below in the relevant  platform-specific  sec‐
74       tion.
75
76       When  using  a  SCSI scanner, ensure that the access permission for the
77       generic SCSI device is set appropriately.  We recommend to add a  group
78       "scanner"  to  /etc/group  which  contains  all  users that should have
79       access to the scanner.  The permission of the device should then be set
80       to  allow  group read and write access.  For example, if the scanner is
81       at generic SCSI device /dev/sg0, then the following two commands  would
82       set the permission correctly:
83
84              $ chgrp scanner /dev/sg0
85              $ chmod 660 /dev/sg0
86
87       When  your  system uses the device filesystem (devfs), you have to edit
88       /etc/devfs/perms.  There you should search the line
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90              REGISTER ^sg[^/]* PERMISSIONS root.root 0600
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92       and add a new line (eg. for changing permissions of sg4):
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94              REGISTER ^sg4 PERMISSIONS root.scanner 0660
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FREEBSD INFO

97       Auto-configuration using the "scsi *" lines in the  config  files  only
98       works  if  the  user  running  the  frontend  has  read/write  acces to
99       /dev/xpt0. Instead, you can also set a link /dev/scanner to the  appro‐
100       priate /dev/uk device.
101
102              Adaptec AHA1542CF
103                     Reported  to  work fine under FreeBSD 2.2.2R with the aha
104                     driver.
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106              Adaptec 2940
107                     Reported to work fine under FreeBSD 2.2.2.
108
109              Adaptec 1522
110                     The scanner probes ok but any attempt to access it  hangs
111                     the  entire  system. It looks like something is disabling
112                     interrupts and then not re-enabling  them,  so  it  looks
113                     like a bug in the FreeBSD aic driver.
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115              Adaptec 1505
116                     Works  on  FreeBSD  2.2.5R  and 3.0 using the aic driver,
117                     provided that Plug-and-Play support is  disabled  on  the
118                     card.  If there are no uk devices, just do a ``sh MAKEDEV
119                     uk0'' in the /dev directory. The scanner should  then  be
120                     accessible as /dev/uk0 if it was probed during boot.
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122              Tekram DC390
123                     Reported  to  work fine under FreeBSD 2.2.2R with the amd
124                     driver.
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126

LINUX INFO

128       First, make sure your kernel has  SCSI  generic  support  enabled.   In
129       ``make xconfig'', this shows up under ``SCSI support->SCSI generic sup‐
130       port''.
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132       To keep scanning times to a minimum, it is strongly recommended to  use
133       a large buffer size for the generic SCSI driver. From SG driver version
134       2.0 on, the maximum buffer size can be changed at program run time, and
135       there  is  no  restriction  in size. This driver version is part of the
136       Linux kernels from version 2.2.7 on. If the new SG driver is  available
137       some  backends  (e.g. sane-umax, sane-mustek, sane-sharp) automatically
138       request larger scsi  buffers.  If  a  backend  does  not  automatically
139       request   a   larger   scsi   buffer,   set  the  environment  variable
140       SANE_SG_BUFFERSIZE to the desired buffer size in bytes. It is not  rec‐
141       ommended  to use more than 1 MB, because for large values the probabil‐
142       ity increases that the SG driver cannot  allocate  the  necessary  buf‐
143       fer(s).  For  ISA  cards,  even  1 MB might be a too large value. For a
144       detailed  discussion  of  memory  issues  of   the   SG   driver,   see
145       http://www.torque.net/sg.
146
147       For  Linux  kernels before version 2.2.7 the size of the buffer is only
148       32KB.  This works, but for many cheaper scanners this  causes  scanning
149       to be slower by about a factor of four than when using a size of 127KB.
150       Linux defines the size of this buffer by macro  SG_BIG_BUFF  in  header
151       file  /usr/include/scsi/sg.h.   Unless  a  system is seriously short on
152       memory, it is recommended to increase this value to the  maximum  legal
153       value  of  128*1024-512=130560 bytes.  After changing this value, it is
154       necessary to recompile both the kernel (or the SCSI generic module) and
155       the  SCSI backends. Keep in mind that this is only necessary with older
156       Linux kernels.
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158
159       A common issue with SCSI scanners is what to do  when  you  booted  the
160       system  while  the scanner was turned off?  In such a case, the scanner
161       won't be recognized by the kernel and SANE won't be able to access  it.
162       Fortunately,  Linux  provides a simple mechanism to probe a SCSI device
163       on demand.  Suppose you have a scanner connected to SCSI bus 2 and  the
164       scanner  has a SCSI id of 5.  When the system is up and running and the
165       scanner is turned on, you can issue the command:
166
167              echo "scsi add-single-device 2 0 5 0" > /proc/scsi/scsi
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169       and the kernel will probe and recognize your scanner (this needs to  be
170       done  as root).  It's also possible to dynamically remove a SCSI device
171       by using the ``remove-single-device''  command.   For  details,  please
172       refer to to the SCSI-2.4-HOWTO.
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174       Scanners  are  known  to  work  with  the following SCSI adapters under
175       Linux. This list isn't complete, usually any SCSI adapter supported  by
176       Linux should work.
177
178              Acard/Advance SCSI adapters
179                     Some  old  versions  of the kernel driver (atp870u.c) cut
180                     the inquiry information.  Therefore the scanner  couldn't
181                     be detected correctly. Use a current kernel.
182
183              Adaptec AHA-1505/AHA-1542/AHA-2940
184                     Reported  to  work  fine  with  Linux  since v2.0. If you
185                     encounter kernel freezes or  other  unexpected  behaviour
186                     get  the  latest  Linux  kernel (2.2.17 seems to work) or
187                     reduce SCSI buffer size to 32 kB.
188
189              ASUS SC200
190                     Reported to work fine with Linux v2.0.
191
192              BusLogic BT958
193                     To configure the BusLogic card, you may  need  to  follow
194                     these     instructions     (contributed     by     Jeremy
195                     <jeremy@xxedgexx.com>): During boot, when  your  BusLogic
196                     adapter  is being initialized, press Ctrl-B to enter your
197                     BusLogic adapter setup.  Choose the  address  which  your
198                     BusLogic  containing  your  scanner  is  located.  Choose
199                     ``SCSI Device Configuration''.  Choose ``Scan SCSI Bus''.
200                     Choose  whatever  SCSI  id that contains your scanner and
201                     then choose ``View/Modify SCSI  configuration''.   Change
202                     ``Negotiation'' to ``async'' and change ``Disconnect'' to
203                     ``off''. Press Esc, save, and Esc  again  until  you  are
204                     asked to reboot.
205
206              NCR/Symbios 53c400/53c400a or Domex DTC3181E/L/LE (DTCT436/436P)
207              ISA SCSI card
208                     This card is supplied by Mustek (and other vendors). It's
209                     supported  since Linux 2.2.  The SCSI cards are supported
210                     by the module g_NCR5380.  It's necessary to tell the ker‐
211                     nel the io port and type of card.  Example for a 53c400a:
212                     ``modprobe  g_NCR5380   ncr_addr=0x280   ncr_53c400a=1''.
213                     Once  the  kernel  detects  the  card, it should work all
214                     right.  However, while it should work, do not expect good
215                     performance  out  of this card---it has no interrupt line
216                     and therefore while a scan is  in  progress,  the  system
217                     becomes  almost  unusable.   You may change the values of
218                     the USLEEP macros in drivers/scsi/g_NCR5380.c.  Some doc‐
219                     umentation is in this file and NCR5380.c.
220
221              NCR/Symbios 810
222                     For  some scanners it may be necessary to disable discon‐
223                     nect/reconnect.  To   achieve   this   use   the   option
224                     ncr53c8xx="disc:n". Some people reported that their scan‐
225                     ner  only  worked  with  the  53c7,8xx  driver,  not  the
226                     ncr53c8xx. Try both if you have trouble.
227                     For  Linux  kernels  before 2.0.33 it may be necessary to
228                     increase the SCSI timeout. The default  timeout  for  the
229                     Linux  kernels  before 2.0.33 is 10 seconds, which is way
230                     too low when scanning large area.  If you get messages of
231                     the  form  ``restart (ncr dead ?)'' in your /var/log/mes‐
232                     sages file or on the system console, it's  an  indication
233                     that  the  timeout  is too short.  In this case, find the
234                     line ``if (np->latetime>10)'' in file  ncr53c8xx.c  (nor‐
235                     mally   in   directory  /usr/src/linux/drivers/scsi)  and
236                     change the constant 10 to, say, 60  (one  minute).   Then
237                     rebuild the kernel/module and try again.
238
239              Tekram DC315
240                     The      driver      can      be      downloaded     from
241                     http://www.garloff.de/kurt/linux/dc395/.  For some  older
242                     scanners  it  may  be  necessary  to disable all the more
243                     advanced  features  by  using  e.g.  modprobe  dc395x_trm
244                     dc395x_trm=7,5,1,32.
245
246              Tekram DC390
247                     Version  1.11  of  the  Tekram  driver seems to work fine
248                     mostly, except that the scan does not terminate  properly
249                     (it causes a SCSI timeout after 10 minutes).  The generic
250                     AM53C974 also seems to work fine and does not suffer from
251                     the timeout problems.
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253

SOLARIS, OPENSTEP AND NEXTSTEP INFO

255       Under  Solaris,  OpenStep  and  NeXTStep,  the generic SCSI device name
256       refers to a SCSI bus,  not  to  an  individual  device.   For  example,
257       /dev/sg0  refers  to  the first SCSI bus.  To tell SANE which device to
258       use, append the character 'a'+target-id to  the  special  device  name.
259       For example, the SCSI device connected to the first SCSI controller and
260       with target-id 0 would be called /dev/sg0a, and the device with target-
261       id 1 on that same bus would be called /dev/sg0b, and so on.
262

ENVIRONMENT

264       SANE_DEBUG_SANEI_SCSI
265              If  the  library  was  compiled with debug support enabled, this
266              environment variable controls the debug level  for  the  generic
267              SCSI  I/O  subsystem.   E.g.,  a value of 128 requests all debug
268              output to be printed by the backend. A value of 255 also  prints
269              kernel  messages  from  the  SCSI  subsystem  (where available).
270              Smaller levels reduce verbosity.
271
272       SANE_SCSICMD_TIMEOUT
273              sets the timeout value for SCSI commands in seconds.  Overriding
274              the  default  value  of 120 seconds should only be necessary for
275              very slow scanners.
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277

SEE ALSO

279       sane(7), sane-find-scanner(1), sane-"backendname"(5), sane-usb(5)
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AUTHOR

283       David Mosberger
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287                                  14 Jul 2008                     sane-scsi(5)
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