Index: cups/dest-options.c
===================================================================
--- cups/dest-options.c	(revision 10298)
+++ cups/dest-options.c	(revision 10299)
@@ -187,7 +187,7 @@
 
           if (!strcmp(temp, "dpi"))
             units_value = IPP_RES_PER_INCH;
-          else if (!strcmp(temp, "dpc"))
+          else if (!strcmp(temp, "dpc") || !strcmp(temp, "dpcm"))
             units_value = IPP_RES_PER_CM;
           else
             return (0);
Index: cups/ipp-support.c
===================================================================
--- cups/ipp-support.c	(revision 10298)
+++ cups/ipp-support.c	(revision 10299)
@@ -3,7 +3,7 @@
  *
  *   Internet Printing Protocol support functions for CUPS.
  *
- *   Copyright 2007-2011 by Apple Inc.
+ *   Copyright 2007-2012 by Apple Inc.
  *   Copyright 1997-2007 by Easy Software Products, all rights reserved.
  *
  *   These coded instructions, statements, and computer programs are the
@@ -487,12 +487,12 @@
             bufptr += snprintf(bufptr, bufend - bufptr + 1, "%dx%d%s",
                                val->resolution.xres, val->resolution.yres,
                                val->resolution.units == IPP_RES_PER_INCH ?
-                                   "dpi" : "dpc");
+                                   "dpi" : "dpcm");
           else
             bufptr += snprintf(temp, sizeof(temp), "%dx%d%s",
                                val->resolution.xres, val->resolution.yres,
                                val->resolution.units == IPP_RES_PER_INCH ?
-                                   "dpi" : "dpc");
+                                   "dpi" : "dpcm");
           break;
 
       case IPP_TAG_DATE :
Index: cups/encode.c
===================================================================
--- cups/encode.c	(revision 10298)
+++ cups/encode.c	(revision 10299)
@@ -3,7 +3,7 @@
  *
  *   Option encoding routines for CUPS.
  *
- *   Copyright 2007-2011 by Apple Inc.
+ *   Copyright 2007-2012 by Apple Inc.
  *   Copyright 1997-2007 by Easy Software Products.
  *
  *   These coded instructions, statements, and computer programs are the
@@ -539,7 +539,8 @@
 	    else
 	      attr->values[j].resolution.yres = attr->values[j].resolution.xres;
 
-	    if (!_cups_strcasecmp(s, "dpc"))
+	    if (!_cups_strcasecmp(s, "dpc") ||
+	        !_cups_strcasecmp(s, "dpcm"))
               attr->values[j].resolution.units = IPP_RES_PER_CM;
             else
               attr->values[j].resolution.units = IPP_RES_PER_INCH;
Index: cups/testipp.c
===================================================================
--- cups/testipp.c	(revision 10298)
+++ cups/testipp.c	(revision 10299)
@@ -3,7 +3,7 @@
  *
  *   IPP test program for CUPS.
  *
- *   Copyright 2007-2011 by Apple Inc.
+ *   Copyright 2007-2012 by Apple Inc.
  *   Copyright 1997-2005 by Easy Software Products.
  *
  *   These coded instructions, statements, and computer programs are the
@@ -901,7 +901,7 @@
       case IPP_TAG_RESOLUTION :
           for (i = 0, val = attr->values; i < attr->num_values; i ++, val ++)
 	    printf(" %dx%d%s", val->resolution.xres, val->resolution.yres,
-	           val->resolution.units == IPP_RES_PER_INCH ? "dpi" : "dpc");
+	           val->resolution.units == IPP_RES_PER_INCH ? "dpi" : "dpcm");
           putchar('\n');
           break;
 
Index: test/ipptool.c
===================================================================
--- test/ipptool.c	(revision 10298)
+++ test/ipptool.c	(revision 10299)
@@ -1608,7 +1608,9 @@
 	        }
 
 	        if (ptr <= token || xres <= 0 || yres <= 0 || !ptr ||
-	            (_cups_strcasecmp(ptr, "dpi") && _cups_strcasecmp(ptr, "dpc") &&
+	            (_cups_strcasecmp(ptr, "dpi") &&
+	             _cups_strcasecmp(ptr, "dpc") &&
+	             _cups_strcasecmp(ptr, "dpcm") &&
 	             _cups_strcasecmp(ptr, "other")))
 	        {
 	          print_fatal_error("Bad resolution value \"%s\" on line %d.",
@@ -1620,7 +1622,8 @@
 	        if (!_cups_strcasecmp(ptr, "dpi"))
 	          attrptr = ippAddResolution(request, group, attr, IPP_RES_PER_INCH,
 	                                     xres, yres);
-	        else if (!_cups_strcasecmp(ptr, "dpc"))
+	        else if (!_cups_strcasecmp(ptr, "dpc") ||
+	                 !_cups_strcasecmp(ptr, "dpcm"))
 	          attrptr = ippAddResolution(request, group, attr, IPP_RES_PER_CM,
 	                                     xres, yres);
 	        else
@@ -2501,8 +2504,8 @@
 	  {
 	    int out_of_order = 0;	/* Are attribute groups out-of-order? */
 	    cupsArrayClear(a);
-	    
 
+
             switch (attrptr->group_tag)
             {
               case IPP_TAG_ZERO :
@@ -2639,7 +2642,7 @@
 		  add_stringf(errors, "EXPECTED: %s OF-TYPE %s (got %s)",
 			      expect->name, expect->of_type,
 			      ippTagString(found->value_tag));
-    
+
 		if (expect->in_group && found->group_tag != expect->in_group)
 		  add_stringf(errors, "EXPECTED: %s IN-GROUP %s (got %s).",
 			      expect->name, ippTagString(expect->in_group),
@@ -3273,7 +3276,9 @@
 	      char	units[6];	/* Units */
 
 	      if (sscanf(token, "%dx%d%5s", &xres, &yres, units) != 3 ||
-		  (_cups_strcasecmp(units, "dpi") && _cups_strcasecmp(units, "dpc") &&
+		  (_cups_strcasecmp(units, "dpi") &&
+		   _cups_strcasecmp(units, "dpc") &&
+		   _cups_strcasecmp(units, "dpcm") &&
 		   _cups_strcasecmp(units, "other")))
 	      {
 		print_fatal_error("Bad resolution value \"%s\" on line %d.",
@@ -3284,7 +3289,8 @@
 	      if (!_cups_strcasecmp(units, "dpi"))
 		ippAddResolution(col, IPP_TAG_ZERO, attr, xres, yres,
 		                 IPP_RES_PER_INCH);
-	      else if (!_cups_strcasecmp(units, "dpc"))
+	      else if (!_cups_strcasecmp(units, "dpc") ||
+	               !_cups_strcasecmp(units, "dpcm"))
 		ippAddResolution(col, IPP_TAG_ZERO, attr, xres, yres,
 		                 IPP_RES_PER_CM);
 	      else
@@ -3679,12 +3685,12 @@
 		     attr->values[i].resolution.xres,
 		     attr->values[i].resolution.yres,
 		     attr->values[i].resolution.units == IPP_RES_PER_INCH ?
-			 "dpi" : "dpc");
+			 "dpi" : "dpcm");
 	    else
 	      printf("%dx%d%s ", attr->values[i].resolution.xres,
 		     attr->values[i].resolution.yres,
 		     attr->values[i].resolution.units == IPP_RES_PER_INCH ?
-			 "dpi" : "dpc");
+			 "dpi" : "dpcm");
 	  break;
 
       case IPP_TAG_DATE :
@@ -3831,7 +3837,7 @@
 	    printf("%dx%d%s ", attr->values[i].resolution.xres,
 		   attr->values[i].resolution.yres,
 		   attr->values[i].resolution.units == IPP_RES_PER_INCH ?
-		       "dpi" : "dpc");
+		       "dpi" : "dpcm");
 	  break;
 
       case IPP_TAG_STRING :
@@ -4554,7 +4560,7 @@
 			attr->values[i].resolution.units ==
 			    IPP_RES_PER_INCH ? "dpi" :
 			    attr->values[i].resolution.units ==
-				IPP_RES_PER_CM ? "dpc" : "unknown");
+				IPP_RES_PER_CM ? "dpcm" : "unknown");
 	  }
 
 	  if (attr->values[i].resolution.yres <= 0)
@@ -4570,7 +4576,7 @@
 			attr->values[i].resolution.units ==
 			    IPP_RES_PER_INCH ? "dpi" :
 			    attr->values[i].resolution.units ==
-				IPP_RES_PER_CM ? "dpc" : "unknown");
+				IPP_RES_PER_CM ? "dpcm" : "unknown");
 	  }
 
 	  if (attr->values[i].resolution.units != IPP_RES_PER_INCH &&
@@ -4586,7 +4592,7 @@
 			attr->values[i].resolution.units ==
 			    IPP_RES_PER_INCH ? "dpi" :
 			    attr->values[i].resolution.units ==
-				IPP_RES_PER_CM ? "dpc" : "unknown");
+				IPP_RES_PER_CM ? "dpcm" : "unknown");
 	  }
 	}
         break;
Index: CHANGES.txt
===================================================================
--- CHANGES.txt	(revision 10298)
+++ CHANGES.txt	(revision 10299)
@@ -4,6 +4,8 @@
 CHANGES IN CUPS V1.6b1
 
 	- Documentation updates (STR #3980)
+	- CUPS now prefers the suffix "dpcm" when reporting resolution in dots-
+	  per-centimeter (STR #4006)
 	- The configure script and build system no longer support building of
 	  separate 32-bit and 64-bit libraries.
 	- The "brightness", "columns", "fitplot", "gamma", "hue",
Index: cgi-bin/ipp-var.c
===================================================================
--- cgi-bin/ipp-var.c	(revision 10298)
+++ cgi-bin/ipp-var.c	(revision 10299)
@@ -3,7 +3,7 @@
  *
  *   CGI <-> IPP variable routines for CUPS.
  *
- *   Copyright 2007-2011 by Apple Inc.
+ *   Copyright 2007-2012 by Apple Inc.
  *   Copyright 1997-2007 by Easy Software Products.
  *
  *   These coded instructions, statements, and computer programs are the
@@ -1219,7 +1219,7 @@
 	             "%dx%d%s", attr->values[i].resolution.xres,
 		     attr->values[i].resolution.yres,
 		     attr->values[i].resolution.units == IPP_RES_PER_INCH ?
-			 "dpi" : "dpc");
+			 "dpi" : "dpcm");
 	    break;
 
 	case IPP_TAG_URI :
Index: scheduler/ipp.c
===================================================================
--- scheduler/ipp.c	(revision 10298)
+++ scheduler/ipp.c	(revision 10299)
@@ -4976,7 +4976,7 @@
 	      cupsFilePrintf(out, "%dx%d%s", attr->values[i].resolution.xres,
 		      attr->values[i].resolution.yres,
 		      attr->values[i].resolution.units == IPP_RES_PER_INCH ?
-			  "dpi" : "dpc");
+			  "dpi" : "dpcm");
 	      break;
 
 	  case IPP_TAG_URI :
@@ -11271,7 +11271,7 @@
           sprintf(value, "%dx%d%s", attr->values[0].resolution.xres,
 	          attr->values[0].resolution.yres,
 		  attr->values[0].resolution.units == IPP_RES_PER_INCH ?
-		      "dpi" : "dpc");
+		      "dpi" : "dpcm");
           printer->num_options = cupsAddOption(name, value,
 					       printer->num_options,
 					       &(printer->options));
Index: scheduler/job.c
===================================================================
--- scheduler/job.c	(revision 10298)
+++ scheduler/job.c	(revision 10299)
@@ -3659,7 +3659,7 @@
 	               "%dx%d%s", attr->values[i].resolution.xres,
 		       attr->values[i].resolution.yres,
 		       attr->values[i].resolution.units == IPP_RES_PER_INCH ?
-			   "dpi" : "dpc");
+			   "dpi" : "dpcm");
 	      break;
 
           case IPP_TAG_STRING :
Index: scheduler/testsub.c
===================================================================
--- scheduler/testsub.c	(revision 10298)
+++ scheduler/testsub.c	(revision 10299)
@@ -3,7 +3,7 @@
  *
  *   Scheduler notification tester for CUPS.
  *
- *   Copyright 2007-2011 by Apple Inc.
+ *   Copyright 2007-2012 by Apple Inc.
  *   Copyright 2006-2007 by Easy Software Products.
  *
  *   These coded instructions, statements, and computer programs are the
@@ -453,7 +453,7 @@
       case IPP_TAG_RESOLUTION :
           for (i = 0, val = attr->values; i < attr->num_values; i ++, val ++)
 	    printf(" %dx%d%s", val->resolution.xres, val->resolution.yres,
-	           val->resolution.units == IPP_RES_PER_INCH ? "dpi" : "dpc");
+	           val->resolution.units == IPP_RES_PER_INCH ? "dpi" : "dpcm");
           putchar('\n');
           break;