Index: backend/runloop.c
===================================================================
--- backend/runloop.c	(revision 7643)
+++ backend/runloop.c	(working copy)
@@ -219,7 +219,7 @@
       FD_SET(print_fd, &input);
     if (use_bc)
       FD_SET(device_fd, &input);
-    if (side_cb)
+    if (!print_bytes && side_cb)
       FD_SET(CUPS_SC_FD, &input);
 
     FD_ZERO(&output);
@@ -260,7 +260,15 @@
     */
 
     if (side_cb && FD_ISSET(CUPS_SC_FD, &input))
+    {
+     /*
+      * Do the side-channel request, then start back over in the select
+      * loop since it may have read from print_fd...
+      */
+
       (*side_cb)(print_fd, device_fd, snmp_fd, addr, use_bc);
+      continue;
+    }
 
    /*
     * Check if we have back-channel data ready...
Index: backend/serial.c
===================================================================
--- backend/serial.c	(revision 7643)
+++ backend/serial.c	(working copy)
@@ -558,7 +558,8 @@
       if (!print_bytes)
 	FD_SET(print_fd, &input);
       FD_SET(device_fd, &input);
-      FD_SET(CUPS_SC_FD, &input);
+      if (!print_bytes)
+        FD_SET(CUPS_SC_FD, &input);
 
       FD_ZERO(&output);
       if (print_bytes)
@@ -572,7 +573,15 @@
       */
 
       if (FD_ISSET(CUPS_SC_FD, &input))
+      {
+       /*
+	* Do the side-channel request, then start back over in the select
+	* loop since it may have read from print_fd...
+	*/
+
         side_cb(print_fd, device_fd, 1);
+	continue;
+      }
 
      /*
       * Check if we have back-channel data ready...