Rephrased the paragraphs about Linux sg

buffer to make it clear, that kernel changes are really only
necessary with older kernels. Fixed torque.net URL. Added comment,
that usually every SCSI adapter should work. Added paragraph about
problems with Acard adapters. Rephrased NCR810 entry.
Henning Meier-Geinitz <henning@meier-geinitz.de>

doc/sane-scsi.man

@@ -1,4 +1,4 @@
-.TH sane-scsi 5 "24 May 2001"
+.TH sane-scsi 5 "10 Jun 2001"
 .IX sane-scsi
 .SH NAME
 sane-scsi - SCSI adapter tips for scanners
@@ -132,38 +132,40 @@ Tekram DC390
 Reported to work fine under FreeBSD 2.2.2R with the
 .B amd
 driver.
+
 .SH LINUX
 First, make sure your kernel has SCSI generic support enabled.  In
 ``make xconfig'', this shows up under ``SCSI support->SCSI generic
 support''.
 .PP
+
 To keep scanning times to a minimum, it is strongly recommended to use a large
-buffer size for the generic SCSI driver.  By default, older Linux kernels use
-a buffer of size 32KB.  This works, but for many cheaper scanners this causes
-scanning to be slower by about a factor of four than when using a size of
-127KB.  Linux defines the size of this buffer by macro
-.B SG_BIG_BUFF
-in header file
-.IR /usr/include/scsi/sg.h .
-Unless a system is seriously short on memory, it is recommended to
-increase this value to the maximum legal value of 128*1024-512=130560
-bytes.  After changing this value, it is necessary to recompile both
-the kernel (or the SCSI generic module) and the SCSI backends.
-.PP
-From SG driver version 2.0 on, the maximum buffer size can
-be changed at program run time, and the restriction to 127 kB is also
-removed. This driver version is part of the Linux kernels from version 
-2.2.7 on. If the new SG driver is available some backends
-(e.g. sane-umax, sane-mustek, sane-sharp) automatically request larger
-scsi buffers. If a backend does not automatically request a larger
-scsi buffer, set the
-environment variable
+buffer size for the generic SCSI driver. From SG driver version 2.0 on, the
+maximum buffer size can be changed at program run time, and there is no restriction in size. This driver version is part of the Linux kernels from
+version 2.2.7 on. If the new SG driver is available some backends
+(e.g. sane-umax, sane-mustek, sane-sharp) automatically request larger scsi
+buffers. If a backend does not automatically request a larger scsi buffer, set
+the environment variable
 .B SANE_SG_BUFFERSIZE
 to the desired buffer size in bytes. It is not recommended to use more 
 than 1 MB, because for large values the probability increases that the 
 SG driver cannot allocate the necessary buffer(s). For ISA cards, even 
 1 MB might be a too large value. For a detailed discussion of memory 
-issues of the SG driver, see http::/www.torque.net/sg.
+issues of the SG driver, see http://www.torque.net/sg.
+.PP
+For Linux kernels before version 2.2.7 the size of the buffer is only 32KB.
+This works, but for many cheaper scanners this causes scanning to be slower by
+about a factor of four than when using a size of 127KB.  Linux defines the
+size of this buffer by macro
+.B SG_BIG_BUFF
+in header file
+.IR /usr/include/scsi/sg.h .
+Unless a system is seriously short on memory, it is recommended to increase
+this value to the maximum legal value of 128*1024-512=130560 bytes.  After
+changing this value, it is necessary to recompile both the kernel (or the SCSI
+generic module) and the SCSI backends. Keep in mind that this is only
+necessary with older Linux kernels.
+
 .PP
 A common issue with SCSI scanners is what to do when you booted
 the system while the scanner was turned off?  In such a case, the
@@ -183,11 +185,16 @@ done as root).  It's also possible to dynamically remove a SCSI device
 by using the ``remove-single-device'' command.  For details, please
 refer to to the SCSI-Programming-HOWTO.
 .PP
-Scanners are known to work with the following SCSI adapters
-under Linux:
+Scanners are known to work with the following SCSI adapters under Linux. This
+list isn't complete, usually any SCSI adapter supported by Linux should work.
 .PP
 .RS
 .TP
+Acard/Advance SCSI adapters
+Some versions of the kernel driver (atp870u.c) cut the inquiry information.
+Therefore the scanner can't be detected correctly. See 
+http://www.meier-geinitz.de/sane/trouble.html#acard for a solution.
+.TP
 Adaptec AHA-1505/AHA-1542/AHA-2940
 Reported to work fine with Linux v2.0. If you encounter kernel freezes
 or other unexpected behaviour get the latest Linux kernel (2.2.17 seems to
@@ -225,22 +232,24 @@ values of the USLEEP macros in drivers/scsi/g_NCR5380.c.  Some documentation is
 in this file and NCR5380.c.
 .TP
 NCR/Symbios 810
-For this card, make sure the SCSI timeout is reasonably big; the
-default timeout for the Linux kernels before 2.0.33 is 10 seconds, which is
-way too low when scanning large area.  If you get messages of the form
-``restart (ncr dead ?)'' in your /var/log/messages file or on the system
-console, it's an indication that the timeout is too short.  In this case, find
-the line ``if (np->latetime>10)'' in file ncr53c8xx.c (normally in directory
-/usr/src/linux/drivers/scsi) and change the constant 10 to, say, 60 (one
-minute).  Then rebuild the kernel/module and try again. For some scanners it
-may be necssary to disable disconnect/reconnect. To achieve this use the
-option ncr53c8xx="disc:n".
+For some scanners it may be necssary to disable disconnect/reconnect. To
+achieve this use the option ncr53c8xx="disc:n".
+.br
+For Linux kernels before 2.0.33 it may be necessary to increase the SCSI
+timeout. The default timeout for the Linux kernels before 2.0.33 is 10
+seconds, which is way too low when scanning large area.  If you get messages
+of the form ``restart (ncr dead ?)'' in your /var/log/messages file or on the
+system console, it's an indication that the timeout is too short.  In this
+case, find the line ``if (np->latetime>10)'' in file ncr53c8xx.c (normally in
+directory /usr/src/linux/drivers/scsi) and change the constant 10 to, say, 60
+(one minute).  Then rebuild the kernel/module and try again.
 .TP
 Tekram DC390
 Version 1.11 of the Tekram driver seems to work fine mostly, except
 that the scan does not terminate properly (it causes a SCSI timeout
 after 10 minutes).  The generic AM53C974 also seems to work fine
 and does not suffer from the timeout problems.
+
 .SH Solaris, OpenStep and NeXTStep
 Under Solaris, OpenStep and NeXTStep, the generic SCSI device name
 refers to a SCSI bus, not to an individual device.  For example,
@@ -262,6 +271,6 @@ environment variable controls the debug level for the generic SCSI I/O
 subsystem.  E.g., a value of 128 requests all debug output to be
 printed.  Smaller levels reduce verbosity.
 .SH "SEE ALSO"
-sane(7), sane-find-scanner(1), sane-"backendname"(5)
+sane(7), sane\-find\-scanner(1), sane\-"backendname"(5)
 .SH AUTHOR
 David Mosberger