Patch: usblp quirk for zebra printers

Patch: usblp quirk for zebra printers

[P. Christeas]

[-- Attachment #1: Type: text/plain, Size: 173 bytes --]

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)


[-- Attachment #2: 0001-USB-Quirk-for-Zebra-printers-not-reporting-their-S.patch --]
[-- Type: text/x-diff, Size: 2668 bytes --]

From 2c87e2cbc8d33b49b6e7a20b9b85570840bb0e12 Mon Sep 17 00:00:00 2001
From: P.Christeas <p_christ@hol.gr>
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@zut.de> */
 	{ 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

Re: Patch: usblp quirk for zebra printers

[Pete Zaitcev]

On Wed, 21 May 2008 20:57:49 +0300, "P. Christeas" <p_christ@hol.gr> wrote:

> 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.

> @@ -1330,6 +1332,23 @@ static int usblp_cache_device_id_string(struct usblp *usblp)
.....
> +		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);

I see...

> Please comment. (and cc. me)

Personally, I don't like this. In kernel, we typically try not to
fake things in lower levels in order to fool upper levels. There are
always knock-off effects. Sometimes we have to do it, but in my
experience CUPS folks always were for doing the right thing.

Let's ask them if extracting the S/N from sysfs is too onerous.
I'm cc-ing this to Tim Waugh.

BTW, Please try to tinker with the following udev ruleset:
BUS="usb", KERNEL="lp[0-9]*", SYSFS{serial}=="XXXXXXX", SYMLINK+="mylp0"
BUS="usb", KERNEL="lp[0-9]*", SYSFS{serial}=="YYYYYYY", SYMLINK+="mylp1"
Encoding your serial numbers into udev rules is not pleasant, but
the above should provide a stop-gap solution without patching kernels.

-- Pete

Re: Patch: usblp quirk for zebra printers

[P. Christeas]

On Thursday 22 May 2008, Pete Zaitcev wrote:
> On Wed, 21 May 2008 20:57:49 +0300, "P. Christeas" <p_christ@hol.gr> wrote:
> > 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.
> Personally, I don't like this. In kernel, we typically try not to
> fake things in lower levels in order to fool upper levels. 
>...
> I'm cc-ing this to Tim Waugh.

I'm now working in a more "politically correct" way around that issue [1]. The 
outline is that we _add_ a backend to CUPS[2], which will bring back USB 
addressing by /dev/.. name. Then, we could implement udev rulesets which will 
create "by-id" symlinks to the usblpX devices. 
My work is at github under "cups-usbbackend".


[1] it is a blocking point for my business, as I cannot attach a second 
printer.
[2] it could remain a complementary package until we really agree we want that 
code mainline.