usblp: quirk flag and device entry for Seiko Epson M129C printer

This patch (as872) adds a device table entry and a new quirk flag to
the usblp driver for the Seiko Epson Receipt printer.  This printer
returns Vendor-Specific values for bInterfaceClass and
bInterfaceSubClass, but the bInterfaceProtocol value is valid and it
works with usblp.  The new quirks flag tells the driver to ignore the
Class and SubClass values in the interface descriptor.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Vojtech Pavlik <vojtech@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/class/usblp.c

@@ -202,6 +202,7 @@ 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 */
 
 static const struct quirk_printer_struct quirk_printers[] = {
 	{ 0x03f0, 0x0004, USBLP_QUIRK_BIDIR }, /* HP DeskJet 895C */
@@ -218,6 +219,7 @@ static const struct quirk_printer_struct quirk_printers[] = {
 	{ 0x0409, 0xf0be, USBLP_QUIRK_BIDIR }, /* NEC Picty920 (HP OEM) */
 	{ 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 */
 	{ 0, 0 }
 };
 
@@ -1048,6 +1050,7 @@ static int usblp_select_alts(struct usblp *usblp)
 		ifd = &if_alt->altsetting[i];
 
 		if (ifd->desc.bInterfaceClass != 7 || ifd->desc.bInterfaceSubClass != 1)
+			if (!(usblp->quirks & USBLP_QUIRK_BAD_CLASS))
 				continue;
 
 		if (ifd->desc.bInterfaceProtocol < USBLP_FIRST_PROTOCOL ||
@@ -1232,6 +1235,7 @@ static struct usb_device_id usblp_ids [] = {
 	{ USB_INTERFACE_INFO(7, 1, 1) },
 	{ USB_INTERFACE_INFO(7, 1, 2) },
 	{ USB_INTERFACE_INFO(7, 1, 3) },
+	{ USB_DEVICE(0x04b8, 0x0202) },	/* Seiko Epson Receipt Printer M129C */
 	{ }						/* Terminating entry */
 };