Fixed problem with SCSI command queuing. Fixed problem that

resulted in black images on some Paragon 6000SP scanners. Added
option to disable backtracking. New version: 1.0-109.
Henning Meier-Geinitz <henning@meier-geinitz.de>

backend/mustek.conf

@@ -13,18 +13,21 @@ scsi MUSTEK * Scanner
 # option buffersize 1024         # set non standard buffer size (in kb)
 # option blocksize 2048          # set non standard block size (in kb)
 # option lineart-fix		 # lineart may be faster with this option off.
+# option disable-backtracking    # faster, but may produce stripes
 
 scsi SCANNER
 # option linedistance-fix        # stripes may go away in color mode
 # option buffersize 1024         # set non standard buffer size (in kb)
 # option blocksize 2048          # set non standard block size (in kb)
 # option lineart-fix		 # lineart may be faster with this option off.
+# option disable-backtracking    # faster, but may produce stripes
 
 /dev/scanner
 # option linedistance-fix        # stripes may go away in color mode
 # option buffersize 1024         # set non standard buffer size (in kb)
 # option blocksize 2048          # set non standard block size (in kb)
 # option lineart-fix		 # lineart may be faster with this option off.
+# option disable-backtracking    # faster, but may produce stripes
 
 #-------------------------- 600 II N ----------------------------------------
 #0x2eb

backend/mustek.desc

@@ -9,7 +9,7 @@
 ;
 
 :backend "mustek"		; name of backend
-:version "1.0-108"		; version of backend
+:version "1.0-109"		; version of backend
 :status :stable			; :alpha, :beta, :stable, :new
 :manpage "sane-mustek"		; name of manpage (if it exists)
 :url "http://www.meier-geinitz.de/sane/"

backend/mustek.h

@@ -62,31 +62,32 @@
 
 /* Flag values */
 /* Scanner types */
-#define MUSTEK_FLAG_THREE_PASS	(1 << 0)   /* three pass scanner */
+#define MUSTEK_FLAG_THREE_PASS	 (1 << 0)   /* three pass scanner */
-#define MUSTEK_FLAG_PARAGON_1   (1 << 1)   /* Paragon series I scanner */
+#define MUSTEK_FLAG_PARAGON_1    (1 << 1)   /* Paragon series I scanner */
-#define MUSTEK_FLAG_PARAGON_2   (1 << 2)   /* Paragon series II (A4) scanner */
+#define MUSTEK_FLAG_PARAGON_2    (1 << 2)   /* Paragon series II(A4) scanner */
-#define MUSTEK_FLAG_SE		(1 << 3)   /* ScanExpress scanner */
+#define MUSTEK_FLAG_SE		 (1 << 3)   /* ScanExpress scanner */
-#define MUSTEK_FLAG_SE_PLUS    	(1 << 4)   /* ScanExpress Plus scanner */
+#define MUSTEK_FLAG_SE_PLUS    	 (1 << 4)   /* ScanExpress Plus scanner */
-#define MUSTEK_FLAG_PRO         (1 << 5)   /* Professional series scanner */
+#define MUSTEK_FLAG_PRO          (1 << 5)   /* Professional series scanner */
-#define MUSTEK_FLAG_N		(1 << 6)   /* N-type scanner (non SCSI) */
+#define MUSTEK_FLAG_N		 (1 << 6)   /* N-type scanner (non SCSI) */
 /* Additional equipment */
-#define MUSTEK_FLAG_ADF		(1 << 7)   /* automatic document feeder */
+#define MUSTEK_FLAG_ADF		 (1 << 7)   /* automatic document feeder */
-#define MUSTEK_FLAG_ADF_READY	(1 << 8)   /* paper present */
+#define MUSTEK_FLAG_ADF_READY	 (1 << 8)   /* paper present */
-#define MUSTEK_FLAG_TA		(1 << 9)   /* transparency adapter */
+#define MUSTEK_FLAG_TA		 (1 << 9)   /* transparency adapter */
 /* Line-distance correction */
-#define MUSTEK_FLAG_LD_NONE	(1 << 10)  /* no line-distance corr */
+#define MUSTEK_FLAG_LD_NONE	 (1 << 10)  /* no line-distance corr */
-#define MUSTEK_FLAG_LD_BLOCK    (1 << 11)  /* blockwise LD corr */
+#define MUSTEK_FLAG_LD_BLOCK     (1 << 11)  /* blockwise LD corr */
-#define MUSTEK_FLAG_LD_N1	(1 << 12)  /* LD corr for N-type v1 */
+#define MUSTEK_FLAG_LD_N1	 (1 << 12)  /* LD corr for N-type v1 */
-#define MUSTEK_FLAG_LD_N2	(1 << 13)  /* LD corr for N-type v2 */
+#define MUSTEK_FLAG_LD_N2	 (1 << 13)  /* LD corr for N-type v2 */
 /* Manual fixes */
-#define MUSTEK_FLAG_LD_FIX	(1 << 14)  /* need line-distance fix? */
+#define MUSTEK_FLAG_LD_FIX	 (1 << 14)  /* need line-distance fix? */
-#define MUSTEK_FLAG_LINEART_FIX	(1 << 15)  /* lineart fix/hack */
+#define MUSTEK_FLAG_LINEART_FIX	 (1 << 15)  /* lineart fix/hack */
-#define MUSTEK_FLAG_USE_EIGHTS	(1 << 16)  /* use 1/8" lengths */
+#define MUSTEK_FLAG_USE_EIGHTS	 (1 << 16)  /* use 1/8" lengths */
-#define MUSTEK_FLAG_FORCE_GAMMA (1 << 17)  /* force gamma table upload */
+#define MUSTEK_FLAG_FORCE_GAMMA  (1 << 17)  /* force gamma table upload */
-#define MUSTEK_FLAG_ENLARGE_X   (1 << 18)  /* need to enlarge x-res */
+#define MUSTEK_FLAG_ENLARGE_X    (1 << 18)  /* need to enlarge x-res */
 #define MUSTEK_FLAG_COVER_SENSOR (1 << 19) /* scanner can detect open cover */
-#define MUSTEK_FLAG_USE_BLOCK	(1 << 20)  /* use blockmode */
+#define MUSTEK_FLAG_USE_BLOCK	 (1 << 20)  /* use blockmode */
-#define MUSTEK_FLAG_LEGAL_SIZE	(1 << 21)  /* scanner has legal size */
+#define MUSTEK_FLAG_LEGAL_SIZE	 (1 << 21)  /* scanner has legal size */
+#define MUSTEK_FLAG_NO_BACKTRACK (1 << 21)  /* scanner has legal size */
 
 /* Source values: */
 #define MUSTEK_SOURCE_FLATBED	0

doc/sane-mustek.man

@@ -1,4 +1,4 @@
-.TH sane-mustek 5 "7 Jul 2001"
+.TH sane-mustek 5 "9 Jul 2001"
 .IX sane-mustek
 .SH NAME
 sane-mustek - SANE backend for Mustek flatbed scanners
@@ -123,6 +123,7 @@ The supported options are
 .BR blocksize ,
 .BR strip-height ,
 .BR disable-double-buffering ,
+.BR disable-backtracking ,
 and
 .B force-wait
 
@@ -187,6 +188,14 @@ the scanner. Try this option if you have trouble while scanning, e.g. SCSI
 errors, freezes, or the first few cm are repeated over and over again in your
 image.
 
+Option
+.B disable-backtracking
+is a positional option. If set, the scanner will not move back its slider
+after each SCSI buffer is filled (`backtracking´). Setting this option will
+lead to faster scans but may also produce horizontal stripes. This option
+doesn't work with every scanner (only some of the paragon models can modify
+backtracking).
+
 Finally,
 .B force-wait
 is a global option. If set, the backend will wait until the device is ready