pixma: new global parameter to set duration of receive timeout loop

The default value for receive timeout loop duration has not been changed.
The loop still takes 8 seconds if a timeout occurs.

backend/pixma_common.c

@@ -651,8 +651,8 @@ pixma_cmd_transaction (pixma_t * s, const void *cmd, unsigned cmdlen,
      immediatly answer with PIXMA_STATUS_BUSY.
 
      Is 8 seconds timeout enough? This affects ALL commands that use
-     pixma_cmd_transaction(). */
+     pixma_cmd_transaction(). Default value set in pixma_open(). */
-  tmo = 8;
+  tmo = s->rec_tmo;
   do
     {
       error = pixma_read (s->io, data, expected_len);
@@ -769,6 +769,7 @@ pixma_open (unsigned devnr, pixma_t ** handle)
   first_pixma = s;
 
   s->cfg = cfg;
+  s->rec_tmo = 8;               /* set receive timeout to 8 seconds */
   error = pixma_connect (devnr, &s->io);
   if (error < 0)
     {

backend/pixma_common.h

@@ -118,6 +118,7 @@ struct pixma_t
   int cancel;			/* NOTE: It can be set in a signal handler. */
   uint32_t events;
   void *subdriver;		/* can be used by model driver. */
+  int rec_tmo;                  /* receive timeout [s] */
 
   /* private */
   uint64_t cur_image_size;