hopefully enable flatbed support

backend/canon_dr-cmd.h

@@ -331,6 +331,7 @@ putnbyte (unsigned char *pnt, unsigned int value, unsigned int nbytes)
 #define set_SSM_BUFF_unk(sb, val)       sb[0x07] = val
 #define set_SSM_BUFF_async(sb, val)     setbitfield(sb+0x0a, 1, 6, val)
 #define set_SSM_BUFF_ald(sb, val)       setbitfield(sb+0x0a, 1, 5, val)
+#define set_SSM_BUFF_fb(sb, val)        setbitfield(sb+0x0a, 1, 4, val)
 
 /* for DO (0x36) page */
 #define SSM_DO_none                     0

backend/canon_dr.c

@@ -2678,6 +2678,9 @@ ssm_buffer (struct scanner *s)
   if(s->s.source == SOURCE_ADF_DUPLEX){
     set_SSM_BUFF_duplex(out, 1);
   }
+  else if(s->s.source == SOURCE_FLATBED){
+    set_SSM_BUFF_fb(out, 1);
+  }
   if(s->buffermode){
     set_SSM_BUFF_async(out, 1);
   }