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 ap‐
14       propriate  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 one to
27       identify scanners by the SCSI vendor and model  string  and/or  by  the
28       SCSI  device address (consisting of bus number, channel number, id, and
29       logical unit number).  The syntax for specifying a scanner in this  way
30       is:
31
32              scsi VENDOR MODEL TYPE BUS CHANNEL ID LUN
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34       where VENDOR is the SCSI vendor string, MODEL is the SCSI model string,
35       TYPE is type SCSI device type string, BUS is the SCSI bus number (named
36       "host"  in  /proc/scsi/scsi), CHANNEL is the SCSI channel number, ID is
37       the SCSI id, and LUN is the logical unit number of the scanner  device.
38       The  first  two  fields  are  strings which must be enclosed in double-
39       quotes if they contain any whitespace.  The remaining four  fields  are
40       non-negative  integer numbers.  The correct values for these fields can
41       be found by using operating system specific tools, e.g.  for  Linux  by
42       looking  at the output of the command cat /proc/scsi/scsi.  To simplify
43       configuration, a field's value can be replaced with an asterisk  symbol
44       (``*'').  An asterisk has the effect that any value is allowed for that
45       particular field.  This can have the effect  that  a  single  scsi-line
46       matches multiple devices.  When this happens, each matching device will
47       be probed by the backend one by  one  and  registered  if  the  backend
48       thinks it is a compatible device.  For example, the line
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50              scsi MUSTEK MFS-06000CX Scanner 0 00 03 00
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52       would attach the Mustek SCSI scanner with the following /proc/scsi/scsi
53       entry:
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55         Host: scsi0 Channel: 00 Id: 03 Lun: 00
56           Vendor: MUSTEK   Model: MFS-06000CX Rev: 4.04
57           Type:   Scanner  ANSI SCSI revision: 0
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59       Usually it's sufficient to use vendor and model strings  only  or  even
60       only the vendor string. The following example
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62              scsi MUSTEK * * * * * *
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64       would have the effect that all SCSI devices in the system with a vendor
65       string of MUSTEK would be probed and recognized by the backend.
66
67       If the remainder of a scsi-string consists of asterisks only,  the  as‐
68       terisks  can be omitted.  For example, the following line is equivalent
69       to the one specified previously:
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71              scsi MUSTEK
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73       On some platforms (e.g., OpenStep), SANE device names  take  a  special
74       form.   This  is explained below in the relevant platform-specific sec‐
75       tion.
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77       When using a SCSI scanner, ensure that the access  permission  for  the
78       generic  SCSI device is set appropriately.  We recommend to add a group
79       "scanner" to /etc/group which contains all users that should  have  ac‐
80       cess  to  the scanner.  The permission of the device should then be set
81       to allow group read and write access.  For example, if the  scanner  is
82       at  generic SCSI device /dev/sg0, then the following two commands would
83       set the permission correctly:
84
85              $ chgrp scanner /dev/sg0
86              $ chmod 660 /dev/sg0
87
88       When your system uses the device filesystem (devfs), you have  to  edit
89       /etc/devfs/perms.  There you should search the line
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91              REGISTER ^sg[^/]* PERMISSIONS root.root 0600
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93       and add a new line (eg. for changing permissions of sg4):
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95              REGISTER ^sg4 PERMISSIONS root.scanner 0660
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FREEBSD INFO

98       Auto-configuration  using  the  "scsi *" lines in the config files only
99       works if the  user  running  the  frontend  has  read/write  access  to
100       /dev/xpt0.  Instead, you can also set a link /dev/scanner to the appro‐
101       priate /dev/uk device.
102
103              Adaptec AHA1542CF
104                     Reported to work fine under FreeBSD 2.2.2R with  the  aha
105                     driver.
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107              Adaptec 2940
108                     Reported to work fine under FreeBSD 2.2.2.
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110              Adaptec 1522
111                     The  scanner probes ok but any attempt to access it hangs
112                     the entire system. It looks like something  is  disabling
113                     interrupts  and  then  not  re-enabling them, so it looks
114                     like a bug in the FreeBSD aic driver.
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116              Adaptec 1505
117                     Works on FreeBSD 2.2.5R and 3.0  using  the  aic  driver,
118                     provided  that  Plug-and-Play  support is disabled on the
119                     card.  If there are no uk devices, just do a  sh  MAKEDEV
120                     uk0 in the /dev directory. The scanner should then be ac‐
121                     cessible as /dev/uk0 if it was probed during boot.
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123              Tekram DC390
124                     Reported to work fine under FreeBSD 2.2.2R with  the  amd
125                     driver.
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127

LINUX INFO

129       First, make sure your kernel has SCSI generic support enabled.  In make
130       xconfig, this shows up under ``SCSI support->SCSI generic support''.
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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(5), sane-mustek(5), sane-sharp(5)) auto‐
138       matically request larger SCSI buffers. If a backend does not  automati‐
139       cally  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 de‐
144       tailed  discussion  of  memory   issues   of   the   SG   driver,   see
145       http://www.torque.net/sg.
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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:
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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 re‐
172       fer 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.
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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.
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183              Adaptec AHA-1505/AHA-1542/AHA-2940
184                     Reported  to  work fine with Linux since v2.0. If you en‐
185                     counter kernel freezes or other unexpected behaviour  get
186                     the  latest Linux kernel (2.2.17 seems to work) or reduce
187                     SCSI buffer size to 32 kB.
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189              ASUS SC200
190                     Reported to work fine with Linux v2.0.
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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.
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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  .   Once
213                     the  kernel  detects  the card, it should work all right.
214                     However, while it should work, do not expect good perfor‐
215                     mance  out  of  this  card---it has no interrupt line and
216                     therefore while a scan is in progress, the system becomes
217                     almost  unusable. You may change the values of the USLEEP
218                     macros in drivers/scsi/g_NCR5380.c.   Some  documentation
219                     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.   (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.
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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 ad‐
243                     vanced  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.
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263

ENVIRONMENT

265       SANE_DEBUG_SANEI_SCSI
266              If the library was compiled with debug support enabled, this en‐
267              vironment variable controls the debug level for the generic SCSI
268              I/O  subsystem.   E.g., a value of 128 requests all debug output
269              to be printed by the backend. A value of 255 also prints  kernel
270              messages  from  the  SCSI  subsystem (where available).  Smaller
271              levels reduce verbosity.
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273       SANE_SCSICMD_TIMEOUT
274              sets the timeout value for SCSI commands in seconds.  Overriding
275              the  default  value  of 120 seconds should only be necessary for
276              very slow scanners.
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278

SEE ALSO

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

284       David Mosberger
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288                                  14 Jul 2008                     sane-scsi(5)
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