Made usb_low_read_rows more robust. Limited maximum block size and

added option for this. New version: 1.0-9.
Henning Meier-Geinitz <henning@meier-geinitz.de>

backend/mustek_usb.c

@@ -46,7 +46,7 @@
    This file implements a SANE backend for Mustek 1200UB and similar 
    flatbed scanners.  */
 
-#define BUILD 8
+#define BUILD 9
 
 #include "../include/sane/config.h"
 
@@ -85,6 +85,9 @@ static SANE_Int num_devices;
 static Mustek_Usb_Device *first_dev;
 static Mustek_Usb_Scanner *first_handle;
 
+/* Maximum amount of data read in one turn from USB */
+static SANE_Word max_block_size = 8 * 1024;
+
 /* Array of newly attached devices */
 static Mustek_Usb_Device **new_dev;	
 
@@ -537,7 +540,8 @@ attach (SANE_String_Const devname, Mustek_Usb_Device ** devp,
       return status;
     }
   dev->chip->scanner_type = scanner_type;
-
+  dev->chip->max_block_size = max_block_size;
+  
   DBG (2, "attach: found %s %s %s at %s\n", dev->sane.vendor, dev->sane.type,
        dev->sane.model, dev->sane.name);
   ++num_devices;
@@ -692,7 +696,7 @@ SANE_Status
 sane_init (SANE_Int * version_code, SANE_Auth_Callback authorize)
 {
   SANE_Char line[PATH_MAX];
-  SANE_Char *word;
+  SANE_Char *word, *end;
   SANE_String_Const cp;
   SANE_Int linenumber;
   FILE *fp;
@@ -749,7 +753,36 @@ sane_init (SANE_Int * version_code, SANE_Auth_Callback authorize)
 	  word = 0;
 	  cp = sanei_config_get_string (cp, &word);
 
-	  if (strcmp (word, "1200ub") == 0)
+	  if (strcmp (word, "max_block_size") == 0)
+	    {
+	      free (word);
+	      word = 0;
+	      cp = sanei_config_get_string (cp, &word);
+	      errno = 0;
+	      max_block_size = strtol (word, &end, 0);
+	      if (end == word)
+		{
+		  DBG(3, "sane-init: config file line %d: max_block_size "
+		      "must have a parameter; using 8192 bytes\n", linenumber);
+		  max_block_size = 8192;
+		}
+	      if (errno)
+		{
+		  DBG(3, "sane-init: config file line %d: max_block_size `%s' "
+		      "is invalid (%s); using 8192 bytes\n",  linenumber,
+		      word, strerror (errno));
+		  max_block_size = 8192;	
+		}
+	      else
+		{
+		  DBG(3, "sane_init: config file line %d: max_block_size set "
+		      "to %d bytes\n", linenumber, max_block_size);
+		}
+	      if (word)
+		free (word);
+	      word = 0;
+	    }
+	  else if (strcmp (word, "1200ub") == 0)
 	    {
 	      if (new_dev_len > 0)
 		{

backend/mustek_usb.conf

@@ -1,6 +1,9 @@
 # mustek_usb.conf: Configuration file for Mustek USB scanner
 # Read man sane-mustek_usb for documentation
 
+# If USB errors occur, using this option may help
+#option max_block_size 1024
+
 # Autodetect 1200 UB and Trust Compact Scan USB 19200
 usb 0x055f 0x0006
 

backend/mustek_usb.desc

@@ -1,6 +1,6 @@
 :backend "mustek_usb"
 :status :new
-:version "1.0-8"
+:version "1.0-9"
 :manpage "sane-mustek_usb"
 :url "http://www.meier-geinitz.de/sane/"
 

backend/mustek_usb_low.c

@@ -2614,39 +2614,44 @@ usb_low_wait_rowing (ma1017 * chip)
 SANE_Status
 usb_low_read_rows (ma1017 * chip, SANE_Byte * data, SANE_Word byte_count)
 {
-  size_t n;
+  size_t n, bytes_total;
   SANE_Status status;
 
   DBG (7, "usb_low_read_rows: start\n");
-  if (!chip->is_opened)
+  if (!(chip->is_opened))
     {
       DBG (3, "usb_low_read_rows: is_opened==SANE_FALSE\n");
       return SANE_STATUS_INVAL;
     }
-  if (!chip->is_rowing)
+  if (!(chip->is_rowing))
     {
       DBG (3, "usb_low_read_rows: is_rowing==SANE_FALSE\n");
       return SANE_STATUS_INVAL;
     }
 
-  n = byte_count;
-  status = sanei_usb_read_bulk (chip->fd, (SANE_Byte *) data, &n);
-  if (status != SANE_STATUS_GOOD)
+  n = MIN(byte_count, chip->max_block_size);
+  bytes_total = 0;
+
+  while ((SANE_Word) bytes_total < byte_count)
     {
-      DBG (7, "usb_low_read_rows: problems during read: %s\n",
-	   sane_strstatus (status));
-      return status;
+      status = sanei_usb_read_bulk (chip->fd, (SANE_Byte *) (data + bytes_total), &n);
+      if (status != SANE_STATUS_GOOD)
+	{
+	  DBG (7, "usb_low_read_rows: problems during read: %s -- exiting\n",
+	       sane_strstatus (status));
+	  return status;
+	}
+      bytes_total += n;
+      if ((SANE_Word) bytes_total != byte_count)
+	{
+	  DBG (7, "usb_low_read_rows:  wanted %d, got %d "
+	       "bytes (%d in total) -- retrying\n", byte_count, (SANE_Word) n,
+	       (SANE_Word) bytes_total);
+	}
+      n = MIN((byte_count - (SANE_Word) bytes_total), chip->max_block_size);
     }
 
-  if ((SANE_Word) n != byte_count)
-    {
-      DBG (7, "usb_low_read_rows: problems during read, wanted %ul, got %ul "
-	   "bytes: %s\n", (unsigned long) byte_count, (unsigned long) n,
-	   sane_strstatus (status));
-      return SANE_STATUS_IO_ERROR;
-    }
-
-  DBG (7, "usb_low_read_rows: exit, read %ul bytes\n", (unsigned long) n);
+  DBG (7, "usb_low_read_rows: exit, read %d bytes\n", (SANE_Word) bytes_total);
   return SANE_STATUS_GOOD;
 }
 

backend/mustek_usb_low.h

@@ -181,6 +181,7 @@ typedef struct ma1017
   Sensor_Type sensor;
   Motor_Type motor;
   Mustek_Type scanner_type;
+  SANE_Word max_block_size;
 }
 ma1017;
 

doc/mustek_usb/mustek_usb.CHANGES

@@ -1,5 +1,17 @@
 CHANGES for the SANE Mustek USB backend
 
+2001-12-08
+  * Release of version 1.0-9. 
+
+2001-12-08
+
+  * Added option max_block_size to limit amount of data acquired in one turn.
+
+2001-12-07
+
+  * usb_low_read_rows: Retry until all the data is received. Set maximum
+    size of data acquired in one turn.
+
 2001-11-15
   * Release of version 1.0-8. 
 

doc/sane-mustek_usb.man

@@ -1,4 +1,4 @@
-.TH sane-mustek 5 "15 Nov 2001"
+.TH sane-mustek 5 "9 Dec 2001"
 .IX sane-mustek_usb
 .SH NAME
 sane-mustek_usb - SANE backend for Mustek USB flatbed scanners
@@ -91,11 +91,18 @@ work, a device name and the option specifying the scanner type must be placed
 in
 .IR mustek_usb.conf .
 .PP
+The global
+.I option max_block_size
+can be used to limit the amount of data acquired in one turn from the USB
+system. It may be woth trying, if USB errors occur.
+.PP
 A sample configuration file is shown below:
 .PP
 .RS
 # Comment
 .br
+option max_block_size 1024
+.br
 usb 0x055f 0x0001
 .br
 /dev/usb/scanner0
@@ -103,10 +110,11 @@ usb 0x055f 0x0001
 option 600cu
 .RE
 .PP
-The first line is ignored. The second line tries to autodetect a scanner with
-vendor id 0x055f and product id 0x0001 (Mustek 1200 CU). The third line tells
-the backend to attach to /dev/usb/scanner0 and the fourth line specifies that
-/dev/usb/scanner 0 is a Mustek 600 CU.
+The first line is ignored. The second line sets the buffer size to a maximum of
+1024 bytes.  The third line tries to autodetect a scanner with vendor id 0x055f
+and product id 0x0001 (Mustek 1200 CU). The fourth line tells the backend to
+attach to /dev/usb/scanner0 and the fifth line specifies that
+/dev/usb/scanner0 is a Mustek 600 CU.
 .SH FILES
 .TP
 .I @CONFIGDIR@/mustek_usb.conf