[PATCH] USB: rndis (4/4) start documenting spec variances

This partially reverts one of the changes in an earlier patch,
starting to document where Microsoft's spec is lying.  Needed
to interop with Windows ME.


The Windows ME implementation of RNDIS relies on a message that
Microsoft's specification says isn't used.  Restore this (removed
in earlier cleanup), and start collecting comments specifically
on where MSFT violates its own specifications.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

drivers/usb/gadget/rndis.c

@@ -252,6 +252,19 @@ static int gen_ndis_query_resp (int configNr, u32 OID, rndis_resp_t *r)
 		retval = 0;
 		break;
 
+	/* The RNDIS specification is incomplete/wrong.   Some versions
+	 * of MS-Windows expect OIDs that aren't specified there.  Other
+	 * versions emit undefined RNDIS messages. DOCUMENT ALL THESE!
+	 */
+	case OID_GEN_MAC_OPTIONS:		/* from WinME */
+		DEBUG("%s: OID_GEN_MAC_OPTIONS\n", __FUNCTION__);
+		length = 4;
+		*((u32 *) resp + 6) = __constant_cpu_to_le32(
+			  NDIS_MAC_OPTION_RECEIVE_SERIALIZED
+			| NDIS_MAC_OPTION_FULL_DUPLEX);
+		retval = 0;
+		break;
+
 	/* statistics OIDs (table 4-2) */
 		
 	/* mandatory */
@@ -1044,6 +1057,10 @@ int rndis_msg_parser (u8 configNr, u8 *buf)
 						 buf);
 		
 	default: 
+		/* At least Windows XP emits some undefined RNDIS messages.
+		 * In one case those messages seemed to relate to the host
+		 * suspending itself.
+		 */
 		printk (KERN_WARNING
 			"%s: unknown RNDIS message 0x%08X len %d\n", 
 			__FUNCTION__ , MsgType, MsgLength);