Patch: usblp quirk for zebra printers

[P. Christeas]

Hi,
I guess such a quirk may be a little odd, but it has been a blocking point in 
my system not being able to support more than one printer.

Please comment. (and cc. me)

From 2c87e2cbc8d33b49b6e7a20b9b85570840bb0e12 Mon Sep 17 00:00:00 2001
From: P.Christeas <p_christ@xxxxxx>
Date: Wed, 21 May 2008 20:47:52 +0300
Subject: [PATCH] USB: Quirk for Zebra printers not reporting their S/N.

Those printers (and maybe others) don't report their Serial
Number as a part of their IEEE1284 device id string. Thus,
printing backends like CUPS cannot select among multiple
devices at the same host.
Workaround this situation by appending the SN in usblp.c .
---
 drivers/usb/class/usblp.c |   19 +++++++++++++++++++
 1 files changed, 19 insertions(+), 0 deletions(-)

diff --git a/drivers/usb/class/usblp.c b/drivers/usb/class/usblp.c
index 0647164..a4d324b 100644
--- a/drivers/usb/class/usblp.c
+++ b/drivers/usb/class/usblp.c
@@ -210,6 +210,7 @@ struct quirk_printer_struct {
 #define USBLP_QUIRK_BIDIR	0x1	/* reports bidir but requires unidirectional mode (no INs/reads) */
 #define USBLP_QUIRK_USB_INIT	0x2	/* needs vendor USB init string */
 #define USBLP_QUIRK_BAD_CLASS	0x4	/* descriptor uses vendor-specific Class or SubClass */
+#define USBLP_QUIRK_ID_NO_SERIAL 0x8	/* Printer does not report its serial no. in GET_ID request */
 
 static const struct quirk_printer_struct quirk_printers[] = {
 	{ 0x03f0, 0x0004, USBLP_QUIRK_BIDIR }, /* HP DeskJet 895C */
@@ -227,6 +228,7 @@ static const struct quirk_printer_struct quirk_printers[] = {
 	{ 0x0409, 0xf1be, USBLP_QUIRK_BIDIR }, /* NEC Picty800 (HP OEM) */
 	{ 0x0482, 0x0010, USBLP_QUIRK_BIDIR }, /* Kyocera Mita FS 820, by zut <kernel@xxxxxx> */
 	{ 0x04b8, 0x0202, USBLP_QUIRK_BAD_CLASS }, /* Seiko Epson Receipt Printer M129C */
+	{ 0x0a5f, 0x000a, USBLP_QUIRK_ID_NO_SERIAL }, /* Zebra printers don't report their serial */
 	{ 0, 0 }
 };
 
@@ -1330,6 +1332,23 @@ static int usblp_cache_device_id_string(struct usblp *usblp)
 		length = 2;
 	else if (length >= USBLP_DEVICE_ID_SIZE)
 		length = USBLP_DEVICE_ID_SIZE - 1;
+	
+	/* If printer doesn't report its serial, we append it */
+	if ((usblp->quirks & USBLP_QUIRK_ID_NO_SERIAL) && (usblp->dev->serial) &&
+		(length + strlen(usblp->dev->serial) + 5 <USBLP_DEVICE_ID_SIZE) ) {
+		
+		if (usblp->device_id_string[length-1] != ';')
+			usblp->device_id_string[length++]= ';';
+
+		strcpy(&usblp->device_id_string[length],"SN:");
+		length+=3;
+		strcat(&usblp->device_id_string[length],usblp->dev->serial);
+		length += strlen(usblp->dev->serial);
+		usblp->device_id_string[length++]= ';';
+
+		*((__be16 *)usblp->device_id_string) = cpu_to_be16(length);
+	}
+	
 	usblp->device_id_string[length] = '\0';
 
 	dbg("usblp%d Device ID string [len=%d]=\"%s\"",
-- 
1.5.4.3