new detailled description for the installation of SANE backend

ChangeLog

@@ -1,3 +1,7 @@
+2012-07-26 Rolf Bensch <rolf at bensch hyphen online dot de>
+	* README.linux: 
+	New detailled description for the installation of SANE backend.
+
 2012-07-24 m. allan noah <kitno455 at gmail dot com>
 	* backend/kvs40xx_opt.c: Oops- it is new
 	* doc/descriptions/kvs40xx.desc: Fix typo (Yuri Chornoivan)

README.linux

@@ -162,3 +162,132 @@ The Intel C++ Compiler for IA32 and IA64 isn't supported yet. If you want
   #elif defined(__ICC) && defined(HAVE_ASM_IO_H)
   # include <asm/io.h>
   #endif
+
+Installation
+============
+
+Get the latest SANE backend from git.
+  You can download daily git snapshot from here: 
+
+  http://www.sane-project.org/snapshots/.
+
+  If you prefer to use git, you can fetch a read-only copy of the git tree with
+  this command:
+
+  $ git clone git://git.debian.org/sane/sane-backends.git
+  
+You need to install SANE backend on a terminal window from inside sane-backends 
+  source folder.
+  
+If you already are using a self compiled SANE backend and just fetched a new 
+  copy of the git tree or if you patched some source files, there is no need to
+  follow the installation procedure again. You only need to make and install 
+  libsane:
+  
+  $ make && sudo make install
+
+Read the file README and this file.
+
+Install missing development packages with your prefered package manager:
+  libusb-dev
+
+Search the location where your system installed libsane.so.1.
+  Each distribution uses different folders and package names for the libraries.
+  
+  On systems with DEB packaging (e.g. Debian, [KX]Ubuntu, LinuxMint) you can 
+    search the location of libsane with this command (the response can be 
+    different to this example):
+
+    $ dpkg -L libsane | grep libsane.so.1
+    /usr/lib/libsane.so.1.0.20
+    /usr/lib/libsane.so.1
+
+  On systems with RPM packaging (e.g. Redhat, Fedora, openSUSE) you can search
+    the location of libsane with one of these commands (the response can be 
+    different to these examples):
+
+    $ rpm -ql sane-backends | grep libsane.so.1  <==  needed for openSUSE 12.1
+    /usr/lib/libsane.so.1
+    /usr/lib/libsane.so.1.0.22
+  
+    or
+  
+    $ rpm -ql sane-backends-libs | grep libsane.so.1  <==  needed for Fedora 17
+    /usr/lib/libsane.so.1
+    /usr/lib/libsane.so.1.0.22
+	
+  In the examples above /usr/lib is the folder we are looking for. 
+  
+  During the installation process described below please replace /usr/lib with 
+  the location of your system's libsane.
+
+Decide where you want to install new libsane.
+  You can set symbolic links to new libsane.
+    I assume that new libsane version 1.0.23 will be installed to 
+    /usr/local/lib and your system installed libsane.so.1 to /usr/lib. 
+
+    $ cd /usr/lib 
+    $ sudo ln -sf /usr/local/lib/libsane.so.1.0.23 libsane.so.1
+    $ sudo ln -sf /usr/local/lib/sane/libsane.la libsane.la
+    $ cd -
+
+  Alternatively you can overwrite standard libsane. 
+    Then you need to do some extra configuration for latest SANE backend:
+    
+    $ ./configure --libdir="/usr/lib"
+    
+You also can replace the binaries, configuration, manuals, translations, etc.
+  of your distribution. For more information please read:
+  
+  $ ./configure --help
+
+Configure, make and install latest SANE backend.
+
+  $ ./configure [with your options defined above]
+  $ make && sudo make install
+
+Use the scanner with normal user rights.
+  This only works if udev is installed. Please note that historically not all
+  of the distributions have used the same format for the udev rules file.
+  
+  Copy udev rules file:
+  
+  $ sudo cp tools/udev/libsane.rules /etc/udev/rules.d
+  
+  Reconnect your scanner to the USB bus to activate the new rules file.
+  
+  Your user must be a member of the group scanner. Please use the system tools
+  to check, if this group exists, if needed create this group and join this 
+  group. After this you must logoff and login again.
+
+Test your scanner.
+  First you should check if new libsane is used.
+  
+    $ scanimage -V
+    scanimage (sane-backends) 1.0.23git; backend version 1.0.23
+  
+    This example shows that backend and scanimage are version 1.0.23.
+  
+    $ /usr/bin/scanimage -V
+    scanimage (sane-backends) 1.0.20; backend version 1.0.23
+  
+    This example shows that an old scanimage (1.0.20) uses the backend 1.0.23.
+  
+    If you want to use xsane, start xsane and check the used version with 
+    CTRL - i.
+    
+  Now you can test if your scanner is recognized with normal user rights.
+  
+    $ scanimage -L
+    
+    If your scanner isn't recognized here, try this:
+    
+      $ sudo scanimage -L
+    
+        If this works, your user doesn't have the rights to access the scanner. 
+
+      However, please check and redo the installation steps described above.  
+      If this doesn't help, you can ask the mailing list  
+      <sane-devel@lists.alioth.debian.org> for further support.
+    
+Have a lot of fun with the latest SANE backend.