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usblp.c

/*
 * usblp.c
 *
 * Copyright (c) 1999 Michael Gee   <michael@linuxspecific.com>
 * Copyright (c) 1999 Pavel Machek  <pavel@suse.cz>
 * Copyright (c) 2000 Randy Dunlap  <rdunlap@xenotime.net>
 * Copyright (c) 2000 Vojtech Pavlik      <vojtech@suse.cz>
 # Copyright (c) 2001 Pete Zaitcev  <zaitcev@redhat.com>
 # Copyright (c) 2001 David Paschal <paschal@rcsis.com>
 * Copyright (c) 2006 Oliver Neukum <oliver@neukum.name>
 *
 * USB Printer Device Class driver for USB printers and printer cables
 *
 * Sponsored by SuSE
 *
 * ChangeLog:
 *    v0.1 - thorough cleaning, URBification, almost a rewrite
 *    v0.2 - some more cleanups
 *    v0.3 - cleaner again, waitqueue fixes
 *    v0.4 - fixes in unidirectional mode
 *    v0.5 - add DEVICE_ID string support
 *    v0.6 - never time out
 *    v0.7 - fixed bulk-IN read and poll (David Paschal)
 *    v0.8 - add devfs support
 *    v0.9 - fix unplug-while-open paths
 *    v0.10- remove sleep_on, fix error on oom (oliver@neukum.org)
 *    v0.11 - add proto_bias option (Pete Zaitcev)
 *    v0.12 - add hpoj.sourceforge.net ioctls (David Paschal)
 *    v0.13 - alloc space for statusbuf (<status> not on stack);
 *          use usb_buffer_alloc() for read buf & write buf;
 *      none  - Maintained in Linux kernel after v0.13
 */

/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/lp.h>
#include <linux/mutex.h>
#undef DEBUG
#include <linux/usb.h>

/*
 * Version Information
 */
#define DRIVER_AUTHOR "Michael Gee, Pavel Machek, Vojtech Pavlik, Randy Dunlap, Pete Zaitcev, David Paschal"
#define DRIVER_DESC "USB Printer Device Class driver"

#define USBLP_BUF_SIZE        8192
#define USBLP_BUF_SIZE_IN     1024
#define USBLP_DEVICE_ID_SIZE  1024

/* ioctls: */
#define IOCNR_GET_DEVICE_ID         1
#define IOCNR_GET_PROTOCOLS         2
#define IOCNR_SET_PROTOCOL          3
#define IOCNR_HP_SET_CHANNEL        4
#define IOCNR_GET_BUS_ADDRESS       5
#define IOCNR_GET_VID_PID           6
#define IOCNR_SOFT_RESET            7
/* Get device_id string: */
#define LPIOC_GET_DEVICE_ID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_DEVICE_ID, len)
/* The following ioctls were added for http://hpoj.sourceforge.net: */
/* Get two-int array:
 * [0]=current protocol (1=7/1/1, 2=7/1/2, 3=7/1/3),
 * [1]=supported protocol mask (mask&(1<<n)!=0 means 7/1/n supported): */
#define LPIOC_GET_PROTOCOLS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_PROTOCOLS, len)
/* Set protocol (arg: 1=7/1/1, 2=7/1/2, 3=7/1/3): */
#define LPIOC_SET_PROTOCOL _IOC(_IOC_WRITE, 'P', IOCNR_SET_PROTOCOL, 0)
/* Set channel number (HP Vendor-specific command): */
#define LPIOC_HP_SET_CHANNEL _IOC(_IOC_WRITE, 'P', IOCNR_HP_SET_CHANNEL, 0)
/* Get two-int array: [0]=bus number, [1]=device address: */
#define LPIOC_GET_BUS_ADDRESS(len) _IOC(_IOC_READ, 'P', IOCNR_GET_BUS_ADDRESS, len)
/* Get two-int array: [0]=vendor ID, [1]=product ID: */
#define LPIOC_GET_VID_PID(len) _IOC(_IOC_READ, 'P', IOCNR_GET_VID_PID, len)
/* Perform class specific soft reset */
#define LPIOC_SOFT_RESET _IOC(_IOC_NONE, 'P', IOCNR_SOFT_RESET, 0);

/*
 * A DEVICE_ID string may include the printer's serial number.
 * It should end with a semi-colon (';').
 * An example from an HP 970C DeskJet printer is (this is one long string,
 * with the serial number changed):
MFG:HEWLETT-PACKARD;MDL:DESKJET 970C;CMD:MLC,PCL,PML;CLASS:PRINTER;DESCRIPTION:Hewlett-Packard DeskJet 970C;SERN:US970CSEPROF;VSTATUS:$HB0$NC0,ff,DN,IDLE,CUT,K1,C0,DP,NR,KP000,CP027;VP:0800,FL,B0;VJ:                    ;
 */

/*
 * USB Printer Requests
 */

#define USBLP_REQ_GET_ID                  0x00
#define USBLP_REQ_GET_STATUS              0x01
#define USBLP_REQ_RESET                   0x02
#define USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST     0x00  /* HP Vendor-specific */

#define USBLP_MINORS          16
#define USBLP_MINOR_BASE      0

#define USBLP_CTL_TIMEOUT     5000              /* 5 seconds */

#define USBLP_FIRST_PROTOCOL  1
#define USBLP_LAST_PROTOCOL   3
#define USBLP_MAX_PROTOCOLS   (USBLP_LAST_PROTOCOL+1)

/*
 * some arbitrary status buffer size;
 * need a status buffer that is allocated via kmalloc(), not on stack
 */
#define STATUS_BUF_SIZE       8

/*
 * Locks down the locking order:
 * ->wmut locks wstatus.
 * ->mut locks the whole usblp, except [rw]complete, and thus, by indirection,
 * [rw]status. We only touch status when we know the side idle.
 * ->lock locks what interrupt accesses.
 */
struct usblp {
      struct usb_device       *dev;             /* USB device */
      struct mutex            wmut;
      struct mutex            mut;
      spinlock_t        lock;       /* locks rcomplete, wcomplete */
      char              *readbuf;         /* read transfer_buffer */
      char              *statusbuf;       /* status transfer_buffer */
      struct usb_anchor urbs;
      wait_queue_head_t rwait, wwait;
      int               readcount;        /* Counter for reads */
      int               ifnum;                  /* Interface number */
      struct usb_interface    *intf;                  /* The interface */
      /* Alternate-setting numbers and endpoints for each protocol
       * (7/1/{index=1,2,3}) that the device supports: */
      struct {
            int                     alt_setting;
            struct usb_endpoint_descriptor      *epwrite;
            struct usb_endpoint_descriptor      *epread;
      }                 protocol[USBLP_MAX_PROTOCOLS];
      int               current_protocol;
      int               minor;                  /* minor number of device */
      int               wcomplete, rcomplete;
      int               wstatus;    /* bytes written or error */
      int               rstatus;    /* bytes ready or error */
      unsigned int            quirks;                 /* quirks flags */
      unsigned int            flags;                  /* mode flags */
      unsigned char           used;             /* True if open */
      unsigned char           present;          /* True if not disconnected */
      unsigned char           bidir;                  /* interface is bidirectional */
      unsigned char           sleeping;         /* interface is suspended */
      unsigned char           no_paper;         /* Paper Out happened */
      unsigned char           *device_id_string;      /* IEEE 1284 DEVICE ID string (ptr) */
                                          /* first 2 bytes are (big-endian) length */
};

#ifdef DEBUG
static void usblp_dump(struct usblp *usblp) {
      int p;

      dbg("usblp=0x%p", usblp);
      dbg("dev=0x%p", usblp->dev);
      dbg("present=%d", usblp->present);
      dbg("readbuf=0x%p", usblp->readbuf);
      dbg("readcount=%d", usblp->readcount);
      dbg("ifnum=%d", usblp->ifnum);
    for (p = USBLP_FIRST_PROTOCOL; p <= USBLP_LAST_PROTOCOL; p++) {
      dbg("protocol[%d].alt_setting=%d", p, usblp->protocol[p].alt_setting);
      dbg("protocol[%d].epwrite=%p", p, usblp->protocol[p].epwrite);
      dbg("protocol[%d].epread=%p", p, usblp->protocol[p].epread);
    }
      dbg("current_protocol=%d", usblp->current_protocol);
      dbg("minor=%d", usblp->minor);
      dbg("wstatus=%d", usblp->wstatus);
      dbg("rstatus=%d", usblp->rstatus);
      dbg("quirks=%d", usblp->quirks);
      dbg("used=%d", usblp->used);
      dbg("bidir=%d", usblp->bidir);
      dbg("sleeping=%d", usblp->sleeping);
      dbg("device_id_string=\"%s\"",
            usblp->device_id_string ?
                  usblp->device_id_string + 2 :
                  (unsigned char *)"(null)");
}
#endif

/* Quirks: various printer quirks are handled by this table & its flags. */

struct quirk_printer_struct {
      __u16 vendorId;
      __u16 productId;
      unsigned int quirks;
};

#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 */
      { 0x03f0, 0x0104, USBLP_QUIRK_BIDIR }, /* HP DeskJet 880C */
      { 0x03f0, 0x0204, USBLP_QUIRK_BIDIR }, /* HP DeskJet 815C */
      { 0x03f0, 0x0304, USBLP_QUIRK_BIDIR }, /* HP DeskJet 810C/812C */
      { 0x03f0, 0x0404, USBLP_QUIRK_BIDIR }, /* HP DeskJet 830C */
      { 0x03f0, 0x0504, USBLP_QUIRK_BIDIR }, /* HP DeskJet 885C */
      { 0x03f0, 0x0604, USBLP_QUIRK_BIDIR }, /* HP DeskJet 840C */   
      { 0x03f0, 0x0804, USBLP_QUIRK_BIDIR }, /* HP DeskJet 816C */   
      { 0x03f0, 0x1104, USBLP_QUIRK_BIDIR }, /* HP Deskjet 959C */
      { 0x0409, 0xefbe, USBLP_QUIRK_BIDIR }, /* NEC Picty900 (HP OEM) */
      { 0x0409, 0xbef4, USBLP_QUIRK_BIDIR }, /* NEC Picty760 (HP OEM) */
      { 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 }
};

static int usblp_wwait(struct usblp *usblp, int nonblock);
static int usblp_wtest(struct usblp *usblp, int nonblock);
static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock);
static int usblp_rtest(struct usblp *usblp, int nonblock);
static int usblp_submit_read(struct usblp *usblp);
static int usblp_select_alts(struct usblp *usblp);
static int usblp_set_protocol(struct usblp *usblp, int protocol);
static int usblp_cache_device_id_string(struct usblp *usblp);

/* forward reference to make our lives easier */
static struct usb_driver usblp_driver;
static DEFINE_MUTEX(usblp_mutex);   /* locks the existence of usblp's */

/*
 * Functions for usblp control messages.
 */

static int usblp_ctrl_msg(struct usblp *usblp, int request, int type, int dir, int recip, int value, void *buf, int len)
{
      int retval;
      int index = usblp->ifnum;

      /* High byte has the interface index.
         Low byte has the alternate setting.
       */
      if ((request == USBLP_REQ_GET_ID) && (type == USB_TYPE_CLASS)) {
        index = (usblp->ifnum<<8)|usblp->protocol[usblp->current_protocol].alt_setting;
      }

      retval = usb_control_msg(usblp->dev,
            dir ? usb_rcvctrlpipe(usblp->dev, 0) : usb_sndctrlpipe(usblp->dev, 0),
            request, type | dir | recip, value, index, buf, len, USBLP_CTL_TIMEOUT);
      dbg("usblp_control_msg: rq: 0x%02x dir: %d recip: %d value: %d idx: %d len: %#x result: %d",
            request, !!dir, recip, value, index, len, retval);
      return retval < 0 ? retval : 0;
}

#define usblp_read_status(usblp, status)\
      usblp_ctrl_msg(usblp, USBLP_REQ_GET_STATUS, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, 0, status, 1)
#define usblp_get_id(usblp, config, id, maxlen)\
      usblp_ctrl_msg(usblp, USBLP_REQ_GET_ID, USB_TYPE_CLASS, USB_DIR_IN, USB_RECIP_INTERFACE, config, id, maxlen)
#define usblp_reset(usblp)\
      usblp_ctrl_msg(usblp, USBLP_REQ_RESET, USB_TYPE_CLASS, USB_DIR_OUT, USB_RECIP_OTHER, 0, NULL, 0)

#define usblp_hp_channel_change_request(usblp, channel, buffer) \
      usblp_ctrl_msg(usblp, USBLP_REQ_HP_CHANNEL_CHANGE_REQUEST, USB_TYPE_VENDOR, USB_DIR_IN, USB_RECIP_INTERFACE, channel, buffer, 1)

/*
 * See the description for usblp_select_alts() below for the usage
 * explanation.  Look into your /proc/bus/usb/devices and dmesg in
 * case of any trouble.
 */
static int proto_bias = -1;

/*
 * URB callback.
 */

static void usblp_bulk_read(struct urb *urb)
{
      struct usblp *usblp = urb->context;
      int status = urb->status;

      if (usblp->present && usblp->used) {
            if (status)
                  printk(KERN_WARNING "usblp%d: "
                      "nonzero read bulk status received: %d\n",
                      usblp->minor, status);
      }
      spin_lock(&usblp->lock);
      if (status < 0)
            usblp->rstatus = status;
      else
            usblp->rstatus = urb->actual_length;
      usblp->rcomplete = 1;
      wake_up(&usblp->rwait);
      spin_unlock(&usblp->lock);

      usb_free_urb(urb);
}

static void usblp_bulk_write(struct urb *urb)
{
      struct usblp *usblp = urb->context;
      int status = urb->status;

      if (usblp->present && usblp->used) {
            if (status)
                  printk(KERN_WARNING "usblp%d: "
                      "nonzero write bulk status received: %d\n",
                      usblp->minor, status);
      }
      spin_lock(&usblp->lock);
      if (status < 0)
            usblp->wstatus = status;
      else
            usblp->wstatus = urb->actual_length;
      usblp->no_paper = 0;
      usblp->wcomplete = 1;
      wake_up(&usblp->wwait);
      spin_unlock(&usblp->lock);

      usb_free_urb(urb);
}

/*
 * Get and print printer errors.
 */

static const char *usblp_messages[] = { "ok", "out of paper", "off-line", "on fire" };

static int usblp_check_status(struct usblp *usblp, int err)
{
      unsigned char status, newerr = 0;
      int error;

      mutex_lock(&usblp->mut);
      if ((error = usblp_read_status(usblp, usblp->statusbuf)) < 0) {
            mutex_unlock(&usblp->mut);
            if (printk_ratelimit())
                  printk(KERN_ERR
                        "usblp%d: error %d reading printer status\n",
                        usblp->minor, error);
            return 0;
      }
      status = *usblp->statusbuf;
      mutex_unlock(&usblp->mut);

      if (~status & LP_PERRORP)
            newerr = 3;
      if (status & LP_POUTPA)
            newerr = 1;
      if (~status & LP_PSELECD)
            newerr = 2;

      if (newerr != err) {
            printk(KERN_INFO "usblp%d: %s\n",
               usblp->minor, usblp_messages[newerr]);
      }

      return newerr;
}

static int handle_bidir (struct usblp *usblp)
{
      if (usblp->bidir && usblp->used && !usblp->sleeping) {
            if (usblp_submit_read(usblp) < 0)
                  return -EIO;
      }
      return 0;
}

/*
 * File op functions.
 */

static int usblp_open(struct inode *inode, struct file *file)
{
      int minor = iminor(inode);
      struct usblp *usblp;
      struct usb_interface *intf;
      int retval;

      if (minor < 0)
            return -ENODEV;

      mutex_lock (&usblp_mutex);

      retval = -ENODEV;
      intf = usb_find_interface(&usblp_driver, minor);
      if (!intf) {
            goto out;
      }
      usblp = usb_get_intfdata (intf);
      if (!usblp || !usblp->dev || !usblp->present)
            goto out;

      retval = -EBUSY;
      if (usblp->used)
            goto out;

      /*
       * We do not implement LP_ABORTOPEN/LPABORTOPEN for two reasons:
       *  - We do not want persistent state which close(2) does not clear
       *  - It is not used anyway, according to CUPS people
       */

      retval = usb_autopm_get_interface(intf);
      if (retval < 0)
            goto out;
      usblp->used = 1;
      file->private_data = usblp;

      usblp->wcomplete = 1; /* we begin writeable */
      usblp->wstatus = 0;
      usblp->rcomplete = 0;

      if (handle_bidir(usblp) < 0) {
            usblp->used = 0;
            file->private_data = NULL;
            retval = -EIO;
      }
out:
      mutex_unlock (&usblp_mutex);
      return retval;
}

static void usblp_cleanup (struct usblp *usblp)
{
      printk(KERN_INFO "usblp%d: removed\n", usblp->minor);

      kfree(usblp->readbuf);
      kfree (usblp->device_id_string);
      kfree (usblp->statusbuf);
      kfree (usblp);
}

static void usblp_unlink_urbs(struct usblp *usblp)
{
      usb_kill_anchored_urbs(&usblp->urbs);
}

static int usblp_release(struct inode *inode, struct file *file)
{
      struct usblp *usblp = file->private_data;

      usblp->flags &= ~LP_ABORT;

      mutex_lock (&usblp_mutex);
      usblp->used = 0;
      if (usblp->present) {
            usblp_unlink_urbs(usblp);
            usb_autopm_put_interface(usblp->intf);
      } else            /* finish cleanup from disconnect */
            usblp_cleanup (usblp);
      mutex_unlock (&usblp_mutex);
      return 0;
}

/* No kernel lock - fine */
static unsigned int usblp_poll(struct file *file, struct poll_table_struct *wait)
{
      int ret;
      unsigned long flags;

      struct usblp *usblp = file->private_data;
      /* Should we check file->f_mode & FMODE_WRITE before poll_wait()? */
      poll_wait(file, &usblp->rwait, wait);
      poll_wait(file, &usblp->wwait, wait);
      spin_lock_irqsave(&usblp->lock, flags);
      ret = ((usblp->bidir && usblp->rcomplete) ? POLLIN  | POLLRDNORM : 0) |
         ((usblp->no_paper || usblp->wcomplete) ? POLLOUT | POLLWRNORM : 0);
      spin_unlock_irqrestore(&usblp->lock, flags);
      return ret;
}

static long usblp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
      struct usblp *usblp = file->private_data;
      int length, err, i;
      unsigned char newChannel;
      int status;
      int twoints[2];
      int retval = 0;

      mutex_lock (&usblp->mut);
      if (!usblp->present) {
            retval = -ENODEV;
            goto done;
      }

      if (usblp->sleeping) {
            retval = -ENODEV;
            goto done;
      }

      dbg("usblp_ioctl: cmd=0x%x (%c nr=%d len=%d dir=%d)", cmd, _IOC_TYPE(cmd),
            _IOC_NR(cmd), _IOC_SIZE(cmd), _IOC_DIR(cmd) );

      if (_IOC_TYPE(cmd) == 'P')    /* new-style ioctl number */

            switch (_IOC_NR(cmd)) {

                  case IOCNR_GET_DEVICE_ID: /* get the DEVICE_ID string */
                        if (_IOC_DIR(cmd) != _IOC_READ) {
                              retval = -EINVAL;
                              goto done;
                        }

                        length = usblp_cache_device_id_string(usblp);
                        if (length < 0) {
                              retval = length;
                              goto done;
                        }
                        if (length > _IOC_SIZE(cmd))
                              length = _IOC_SIZE(cmd); /* truncate */

                        if (copy_to_user((void __user *) arg,
                                    usblp->device_id_string,
                                    (unsigned long) length)) {
                              retval = -EFAULT;
                              goto done;
                        }

                        break;

                  case IOCNR_GET_PROTOCOLS:
                        if (_IOC_DIR(cmd) != _IOC_READ ||
                            _IOC_SIZE(cmd) < sizeof(twoints)) {
                              retval = -EINVAL;
                              goto done;
                        }

                        twoints[0] = usblp->current_protocol;
                        twoints[1] = 0;
                        for (i = USBLP_FIRST_PROTOCOL;
                             i <= USBLP_LAST_PROTOCOL; i++) {
                              if (usblp->protocol[i].alt_setting >= 0)
                                    twoints[1] |= (1<<i);
                        }

                        if (copy_to_user((void __user *)arg,
                                    (unsigned char *)twoints,
                                    sizeof(twoints))) {
                              retval = -EFAULT;
                              goto done;
                        }

                        break;

                  case IOCNR_SET_PROTOCOL:
                        if (_IOC_DIR(cmd) != _IOC_WRITE) {
                              retval = -EINVAL;
                              goto done;
                        }

#ifdef DEBUG
                        if (arg == -10) {
                              usblp_dump(usblp);
                              break;
                        }
#endif

                        usblp_unlink_urbs(usblp);
                        retval = usblp_set_protocol(usblp, arg);
                        if (retval < 0) {
                              usblp_set_protocol(usblp,
                                    usblp->current_protocol);
                        }
                        break;

                  case IOCNR_HP_SET_CHANNEL:
                        if (_IOC_DIR(cmd) != _IOC_WRITE ||
                            le16_to_cpu(usblp->dev->descriptor.idVendor) != 0x03F0 ||
                            usblp->quirks & USBLP_QUIRK_BIDIR) {
                              retval = -EINVAL;
                              goto done;
                        }

                        err = usblp_hp_channel_change_request(usblp,
                              arg, &newChannel);
                        if (err < 0) {
                              err("usblp%d: error = %d setting "
                                    "HP channel",
                                    usblp->minor, err);
                              retval = -EIO;
                              goto done;
                        }

                        dbg("usblp%d requested/got HP channel %ld/%d",
                              usblp->minor, arg, newChannel);
                        break;

                  case IOCNR_GET_BUS_ADDRESS:
                        if (_IOC_DIR(cmd) != _IOC_READ ||
                            _IOC_SIZE(cmd) < sizeof(twoints)) {
                              retval = -EINVAL;
                              goto done;
                        }

                        twoints[0] = usblp->dev->bus->busnum;
                        twoints[1] = usblp->dev->devnum;
                        if (copy_to_user((void __user *)arg,
                                    (unsigned char *)twoints,
                                    sizeof(twoints))) {
                              retval = -EFAULT;
                              goto done;
                        }

                        dbg("usblp%d is bus=%d, device=%d",
                              usblp->minor, twoints[0], twoints[1]);
                        break;

                  case IOCNR_GET_VID_PID:
                        if (_IOC_DIR(cmd) != _IOC_READ ||
                            _IOC_SIZE(cmd) < sizeof(twoints)) {
                              retval = -EINVAL;
                              goto done;
                        }

                        twoints[0] = le16_to_cpu(usblp->dev->descriptor.idVendor);
                        twoints[1] = le16_to_cpu(usblp->dev->descriptor.idProduct);
                        if (copy_to_user((void __user *)arg,
                                    (unsigned char *)twoints,
                                    sizeof(twoints))) {
                              retval = -EFAULT;
                              goto done;
                        }

                        dbg("usblp%d is VID=0x%4.4X, PID=0x%4.4X",
                              usblp->minor, twoints[0], twoints[1]);
                        break;

                  case IOCNR_SOFT_RESET:
                        if (_IOC_DIR(cmd) != _IOC_NONE) {
                              retval = -EINVAL;
                              goto done;
                        }
                        retval = usblp_reset(usblp);
                        break;
                  default:
                        retval = -ENOTTY;
            }
      else  /* old-style ioctl value */
            switch (cmd) {

                  case LPGETSTATUS:
                        if ((retval = usblp_read_status(usblp, usblp->statusbuf))) {
                              if (printk_ratelimit())
                                    printk(KERN_ERR "usblp%d:"
                                        "failed reading printer status (%d)\n",
                                        usblp->minor, retval);
                              retval = -EIO;
                              goto done;
                        }
                        status = *usblp->statusbuf;
                        if (copy_to_user ((void __user *)arg, &status, sizeof(int)))
                              retval = -EFAULT;
                        break;

                  case LPABORT:
                        if (arg)
                              usblp->flags |= LP_ABORT;
                        else
                              usblp->flags &= ~LP_ABORT;
                        break;

                  default:
                        retval = -ENOTTY;
            }

done:
      mutex_unlock (&usblp->mut);
      return retval;
}

static struct urb *usblp_new_writeurb(struct usblp *usblp, int transfer_length)
{
      struct urb *urb;
      char *writebuf;

      if ((writebuf = kmalloc(transfer_length, GFP_KERNEL)) == NULL)
            return NULL;
      if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL) {
            kfree(writebuf);
            return NULL;
      }

      usb_fill_bulk_urb(urb, usblp->dev,
            usb_sndbulkpipe(usblp->dev,
             usblp->protocol[usblp->current_protocol].epwrite->bEndpointAddress),
            writebuf, transfer_length, usblp_bulk_write, usblp);
      urb->transfer_flags |= URB_FREE_BUFFER;

      return urb;
}

static ssize_t usblp_write(struct file *file, const char __user *buffer, size_t count, loff_t *ppos)
{
      struct usblp *usblp = file->private_data;
      struct urb *writeurb;
      int rv;
      int transfer_length;
      ssize_t writecount = 0;

      if (mutex_lock_interruptible(&usblp->wmut)) {
            rv = -EINTR;
            goto raise_biglock;
      }
      if ((rv = usblp_wwait(usblp, !!(file->f_flags & O_NONBLOCK))) < 0)
            goto raise_wait;

      while (writecount < count) {
            /*
             * Step 1: Submit next block.
             */
            if ((transfer_length = count - writecount) > USBLP_BUF_SIZE)
                  transfer_length = USBLP_BUF_SIZE;

            rv = -ENOMEM;
            if ((writeurb = usblp_new_writeurb(usblp, transfer_length)) == NULL)
                  goto raise_urb;
            usb_anchor_urb(writeurb, &usblp->urbs);

            if (copy_from_user(writeurb->transfer_buffer,
                           buffer + writecount, transfer_length)) {
                  rv = -EFAULT;
                  goto raise_badaddr;
            }

            spin_lock_irq(&usblp->lock);
            usblp->wcomplete = 0;
            spin_unlock_irq(&usblp->lock);
            if ((rv = usb_submit_urb(writeurb, GFP_KERNEL)) < 0) {
                  usblp->wstatus = 0;
                  spin_lock_irq(&usblp->lock);
                  usblp->no_paper = 0;
                  usblp->wcomplete = 1;
                  wake_up(&usblp->wwait);
                  spin_unlock_irq(&usblp->lock);
                  if (rv != -ENOMEM)
                        rv = -EIO;
                  goto raise_submit;
            }

            /*
             * Step 2: Wait for transfer to end, collect results.
             */
            rv = usblp_wwait(usblp, !!(file->f_flags&O_NONBLOCK));
            if (rv < 0) {
                  if (rv == -EAGAIN) {
                        /* Presume that it's going to complete well. */
                        writecount += transfer_length;
                  }
                  if (rv == -ENOSPC) {
                        spin_lock_irq(&usblp->lock);
                        usblp->no_paper = 1;    /* Mark for poll(2) */
                        spin_unlock_irq(&usblp->lock);
                        writecount += transfer_length;
                  }
                  /* Leave URB dangling, to be cleaned on close. */
                  goto collect_error;
            }

            if (usblp->wstatus < 0) {
                  rv = -EIO;
                  goto collect_error;
            }
            /*
             * This is critical: it must be our URB, not other writer's.
             * The wmut exists mainly to cover us here.
             */
            writecount += usblp->wstatus;
      }

      mutex_unlock(&usblp->wmut);
      return writecount;

raise_submit:
raise_badaddr:
      usb_unanchor_urb(writeurb);
      usb_free_urb(writeurb);
raise_urb:
raise_wait:
collect_error:          /* Out of raise sequence */
      mutex_unlock(&usblp->wmut);
raise_biglock:
      return writecount ? writecount : rv;
}

/*
 * Notice that we fail to restart in a few cases: on EFAULT, on restart
 * error, etc. This is the historical behaviour. In all such cases we return
 * EIO, and applications loop in order to get the new read going.
 */
static ssize_t usblp_read(struct file *file, char __user *buffer, size_t len, loff_t *ppos)
{
      struct usblp *usblp = file->private_data;
      ssize_t count;
      ssize_t avail;
      int rv;

      if (!usblp->bidir)
            return -EINVAL;

      rv = usblp_rwait_and_lock(usblp, !!(file->f_flags & O_NONBLOCK));
      if (rv < 0)
            return rv;

      if ((avail = usblp->rstatus) < 0) {
            printk(KERN_ERR "usblp%d: error %d reading from printer\n",
                usblp->minor, (int)avail);
            usblp_submit_read(usblp);
            count = -EIO;
            goto done;
      }

      count = len < avail - usblp->readcount ? len : avail - usblp->readcount;
      if (count != 0 &&
          copy_to_user(buffer, usblp->readbuf + usblp->readcount, count)) {
            count = -EFAULT;
            goto done;
      }

      if ((usblp->readcount += count) == avail) {
            if (usblp_submit_read(usblp) < 0) {
                  /* We don't want to leak USB return codes into errno. */
                  if (count == 0)
                        count = -EIO;
                  goto done;
            }
      }

done:
      mutex_unlock (&usblp->mut);
      return count;
}

/*
 * Wait for the write path to come idle.
 * This is called under the ->wmut, so the idle path stays idle.
 *
 * Our write path has a peculiar property: it does not buffer like a tty,
 * but waits for the write to succeed. This allows our ->release to bug out
 * without waiting for writes to drain. But it obviously does not work
 * when O_NONBLOCK is set. So, applications setting O_NONBLOCK must use
 * select(2) or poll(2) to wait for the buffer to drain before closing.
 * Alternatively, set blocking mode with fcntl and issue a zero-size write.
 */
static int usblp_wwait(struct usblp *usblp, int nonblock)
{
      DECLARE_WAITQUEUE(waita, current);
      int rc;
      int err = 0;

      add_wait_queue(&usblp->wwait, &waita);
      for (;;) {
            set_current_state(TASK_INTERRUPTIBLE);
            if (mutex_lock_interruptible(&usblp->mut)) {
                  rc = -EINTR;
                  break;
            }
            rc = usblp_wtest(usblp, nonblock);
            mutex_unlock(&usblp->mut);
            if (rc <= 0)
                  break;

            if (usblp->flags & LP_ABORT) {
                  if (schedule_timeout(msecs_to_jiffies(5000)) == 0) {
                        err = usblp_check_status(usblp, err);
                        if (err == 1) {   /* Paper out */
                              rc = -ENOSPC;
                              break;
                        }
                  }
            } else {
                  schedule();
            }
      }
      set_current_state(TASK_RUNNING);
      remove_wait_queue(&usblp->wwait, &waita);
      return rc;
}

static int usblp_wtest(struct usblp *usblp, int nonblock)
{
      unsigned long flags;

      if (!usblp->present)
            return -ENODEV;
      if (signal_pending(current))
            return -EINTR;
      spin_lock_irqsave(&usblp->lock, flags);
      if (usblp->wcomplete) {
            spin_unlock_irqrestore(&usblp->lock, flags);
            return 0;
      }
      spin_unlock_irqrestore(&usblp->lock, flags);
      if (usblp->sleeping)
            return -ENODEV;
      if (nonblock)
            return -EAGAIN;
      return 1;
}

/*
 * Wait for read bytes to become available. This probably should have been
 * called usblp_r_lock_and_wait(), because we lock first. But it's a traditional
 * name for functions which lock and return.
 *
 * We do not use wait_event_interruptible because it makes locking iffy.
 */
static int usblp_rwait_and_lock(struct usblp *usblp, int nonblock)
{
      DECLARE_WAITQUEUE(waita, current);
      int rc;

      add_wait_queue(&usblp->rwait, &waita);
      for (;;) {
            if (mutex_lock_interruptible(&usblp->mut)) {
                  rc = -EINTR;
                  break;
            }
            set_current_state(TASK_INTERRUPTIBLE);
            if ((rc = usblp_rtest(usblp, nonblock)) < 0) {
                  mutex_unlock(&usblp->mut);
                  break;
            }
            if (rc == 0)      /* Keep it locked */
                  break;
            mutex_unlock(&usblp->mut);
            schedule();
      }
      set_current_state(TASK_RUNNING);
      remove_wait_queue(&usblp->rwait, &waita);
      return rc;
}

static int usblp_rtest(struct usblp *usblp, int nonblock)
{
      unsigned long flags;

      if (!usblp->present)
            return -ENODEV;
      if (signal_pending(current))
            return -EINTR;
      spin_lock_irqsave(&usblp->lock, flags);
      if (usblp->rcomplete) {
            spin_unlock_irqrestore(&usblp->lock, flags);
            return 0;
      }
      spin_unlock_irqrestore(&usblp->lock, flags);
      if (usblp->sleeping)
            return -ENODEV;
      if (nonblock)
            return -EAGAIN;
      return 1;
}

/*
 * Please check ->bidir and other such things outside for now.
 */
static int usblp_submit_read(struct usblp *usblp)
{
      struct urb *urb;
      unsigned long flags;
      int rc;

      rc = -ENOMEM;
      if ((urb = usb_alloc_urb(0, GFP_KERNEL)) == NULL)
            goto raise_urb;

      usb_fill_bulk_urb(urb, usblp->dev,
            usb_rcvbulkpipe(usblp->dev,
              usblp->protocol[usblp->current_protocol].epread->bEndpointAddress),
            usblp->readbuf, USBLP_BUF_SIZE_IN,
            usblp_bulk_read, usblp);
      usb_anchor_urb(urb, &usblp->urbs);

      spin_lock_irqsave(&usblp->lock, flags);
      usblp->readcount = 0; /* XXX Why here? */
      usblp->rcomplete = 0;
      spin_unlock_irqrestore(&usblp->lock, flags);
      if ((rc = usb_submit_urb(urb, GFP_KERNEL)) < 0) {
            dbg("error submitting urb (%d)", rc);
            spin_lock_irqsave(&usblp->lock, flags);
            usblp->rstatus = rc;
            usblp->rcomplete = 1;
            spin_unlock_irqrestore(&usblp->lock, flags);
            goto raise_submit;
      }

      return 0;

raise_submit:
      usb_unanchor_urb(urb);
      usb_free_urb(urb);
raise_urb:
      return rc;
}

/*
 * Checks for printers that have quirks, such as requiring unidirectional
 * communication but reporting bidirectional; currently some HP printers
 * have this flaw (HP 810, 880, 895, etc.), or needing an init string
 * sent at each open (like some Epsons).
 * Returns 1 if found, 0 if not found.
 *
 * HP recommended that we use the bidirectional interface but
 * don't attempt any bulk IN transfers from the IN endpoint.
 * Here's some more detail on the problem:
 * The problem is not that it isn't bidirectional though. The problem
 * is that if you request a device ID, or status information, while
 * the buffers are full, the return data will end up in the print data
 * buffer. For example if you make sure you never request the device ID
 * while you are sending print data, and you don't try to query the
 * printer status every couple of milliseconds, you will probably be OK.
 */
static unsigned int usblp_quirks (__u16 vendor, __u16 product)
{
      int i;

      for (i = 0; quirk_printers[i].vendorId; i++) {
            if (vendor == quirk_printers[i].vendorId &&
                product == quirk_printers[i].productId)
                  return quirk_printers[i].quirks;
      }
      return 0;
}

static const struct file_operations usblp_fops = {
      .owner =    THIS_MODULE,
      .read =           usblp_read,
      .write =    usblp_write,
      .poll =           usblp_poll,
      .unlocked_ioctl = usblp_ioctl,
      .compat_ioctl =         usblp_ioctl,
      .open =           usblp_open,
      .release =  usblp_release,
};

static struct usb_class_driver usblp_class = {
      .name =           "lp%d",
      .fops =           &usblp_fops,
      .minor_base =     USBLP_MINOR_BASE,
};

static ssize_t usblp_show_ieee1284_id(struct device *dev, struct device_attribute *attr, char *buf)
{
      struct usb_interface *intf = to_usb_interface(dev);
      struct usblp *usblp = usb_get_intfdata (intf);

      if (usblp->device_id_string[0] == 0 &&
          usblp->device_id_string[1] == 0)
            return 0;

      return sprintf(buf, "%s", usblp->device_id_string+2);
}

static DEVICE_ATTR(ieee1284_id, S_IRUGO, usblp_show_ieee1284_id, NULL);

static int usblp_probe(struct usb_interface *intf,
                   const struct usb_device_id *id)
{
      struct usb_device *dev = interface_to_usbdev (intf);
      struct usblp *usblp = NULL;
      int protocol;
      int retval;

      /* Malloc and start initializing usblp structure so we can use it
       * directly. */
      if (!(usblp = kzalloc(sizeof(struct usblp), GFP_KERNEL))) {
            retval = -ENOMEM;
            goto abort;
      }
      usblp->dev = dev;
      mutex_init(&usblp->wmut);
      mutex_init (&usblp->mut);
      spin_lock_init(&usblp->lock);
      init_waitqueue_head(&usblp->rwait);
      init_waitqueue_head(&usblp->wwait);
      init_usb_anchor(&usblp->urbs);
      usblp->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
      usblp->intf = intf;

      /* Malloc device ID string buffer to the largest expected length,
       * since we can re-query it on an ioctl and a dynamic string
       * could change in length. */
      if (!(usblp->device_id_string = kmalloc(USBLP_DEVICE_ID_SIZE, GFP_KERNEL))) {
            retval = -ENOMEM;
            goto abort;
      }

      /*
       * Allocate read buffer. We somewhat wastefully
       * malloc both regardless of bidirectionality, because the
       * alternate setting can be changed later via an ioctl.
       */
      if (!(usblp->readbuf = kmalloc(USBLP_BUF_SIZE_IN, GFP_KERNEL))) {
            retval = -ENOMEM;
            goto abort;
      }

      /* Allocate buffer for printer status */
      usblp->statusbuf = kmalloc(STATUS_BUF_SIZE, GFP_KERNEL);
      if (!usblp->statusbuf) {
            retval = -ENOMEM;
            goto abort;
      }

      /* Lookup quirks for this printer. */
      usblp->quirks = usblp_quirks(
            le16_to_cpu(dev->descriptor.idVendor),
            le16_to_cpu(dev->descriptor.idProduct));

      /* Analyze and pick initial alternate settings and endpoints. */
      protocol = usblp_select_alts(usblp);
      if (protocol < 0) {
            dbg("incompatible printer-class device 0x%4.4X/0x%4.4X",
                  le16_to_cpu(dev->descriptor.idVendor),
                  le16_to_cpu(dev->descriptor.idProduct));
            retval = -ENODEV;
            goto abort;
      }

      /* Setup the selected alternate setting and endpoints. */
      if (usblp_set_protocol(usblp, protocol) < 0) {
            retval = -ENODEV; /* ->probe isn't ->ioctl */
            goto abort;
      }

      /* Retrieve and store the device ID string. */
      usblp_cache_device_id_string(usblp);
      retval = device_create_file(&intf->dev, &dev_attr_ieee1284_id);
      if (retval)
            goto abort_intfdata;

#ifdef DEBUG
      usblp_check_status(usblp, 0);
#endif

      usb_set_intfdata (intf, usblp);

      usblp->present = 1;

      retval = usb_register_dev(intf, &usblp_class);
      if (retval) {
            printk(KERN_ERR "usblp: Not able to get a minor"
                " (base %u, slice default): %d\n",
                USBLP_MINOR_BASE, retval);
            goto abort_intfdata;
      }
      usblp->minor = intf->minor;
      printk(KERN_INFO "usblp%d: USB %sdirectional printer dev %d "
            "if %d alt %d proto %d vid 0x%4.4X pid 0x%4.4X\n",
            usblp->minor, usblp->bidir ? "Bi" : "Uni", dev->devnum,
            usblp->ifnum,
            usblp->protocol[usblp->current_protocol].alt_setting,
            usblp->current_protocol,
            le16_to_cpu(usblp->dev->descriptor.idVendor),
            le16_to_cpu(usblp->dev->descriptor.idProduct));

      return 0;

abort_intfdata:
      usb_set_intfdata (intf, NULL);
      device_remove_file(&intf->dev, &dev_attr_ieee1284_id);
abort:
      if (usblp) {
            kfree(usblp->readbuf);
            kfree(usblp->statusbuf);
            kfree(usblp->device_id_string);
            kfree(usblp);
      }
      return retval;
}

/*
 * We are a "new" style driver with usb_device_id table,
 * but our requirements are too intricate for simple match to handle.
 *
 * The "proto_bias" option may be used to specify the preferred protocol
 * for all USB printers (1=7/1/1, 2=7/1/2, 3=7/1/3).  If the device
 * supports the preferred protocol, then we bind to it.
 *
 * The best interface for us is 7/1/2, because it is compatible
 * with a stream of characters. If we find it, we bind to it.
 *
 * Note that the people from hpoj.sourceforge.net need to be able to
 * bind to 7/1/3 (MLC/1284.4), so we provide them ioctls for this purpose.
 *
 * Failing 7/1/2, we look for 7/1/3, even though it's probably not
 * stream-compatible, because this matches the behaviour of the old code.
 *
 * If nothing else, we bind to 7/1/1 - the unidirectional interface.
 */
static int usblp_select_alts(struct usblp *usblp)
{
      struct usb_interface *if_alt;
      struct usb_host_interface *ifd;
      struct usb_endpoint_descriptor *epd, *epwrite, *epread;
      int p, i, e;

      if_alt = usblp->intf;

      for (p = 0; p < USBLP_MAX_PROTOCOLS; p++)
            usblp->protocol[p].alt_setting = -1;

      /* Find out what we have. */
      for (i = 0; i < if_alt->num_altsetting; i++) {
            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 ||
                ifd->desc.bInterfaceProtocol > USBLP_LAST_PROTOCOL)
                  continue;

            /* Look for bulk OUT and IN endpoints. */
            epwrite = epread = NULL;
            for (e = 0; e < ifd->desc.bNumEndpoints; e++) {
                  epd = &ifd->endpoint[e].desc;

                  if (usb_endpoint_is_bulk_out(epd))
                        if (!epwrite)
                              epwrite = epd;

                  if (usb_endpoint_is_bulk_in(epd))
                        if (!epread)
                              epread = epd;
            }

            /* Ignore buggy hardware without the right endpoints. */
            if (!epwrite || (ifd->desc.bInterfaceProtocol > 1 && !epread))
                  continue;

            /* Turn off reads for 7/1/1 (unidirectional) interfaces
             * and buggy bidirectional printers. */
            if (ifd->desc.bInterfaceProtocol == 1) {
                  epread = NULL;
            } else if (usblp->quirks & USBLP_QUIRK_BIDIR) {
                  printk(KERN_INFO "usblp%d: Disabling reads from "
                      "problematic bidirectional printer\n",
                      usblp->minor);
                  epread = NULL;
            }

            usblp->protocol[ifd->desc.bInterfaceProtocol].alt_setting =
                        ifd->desc.bAlternateSetting;
            usblp->protocol[ifd->desc.bInterfaceProtocol].epwrite = epwrite;
            usblp->protocol[ifd->desc.bInterfaceProtocol].epread = epread;
      }

      /* If our requested protocol is supported, then use it. */
      if (proto_bias >= USBLP_FIRST_PROTOCOL &&
          proto_bias <= USBLP_LAST_PROTOCOL &&
          usblp->protocol[proto_bias].alt_setting != -1)
            return proto_bias;

      /* Ordering is important here. */
      if (usblp->protocol[2].alt_setting != -1)
            return 2;
      if (usblp->protocol[1].alt_setting != -1)
            return 1;
      if (usblp->protocol[3].alt_setting != -1)
            return 3;

      /* If nothing is available, then don't bind to this device. */
      return -1;
}

static int usblp_set_protocol(struct usblp *usblp, int protocol)
{
      int r, alts;

      if (protocol < USBLP_FIRST_PROTOCOL || protocol > USBLP_LAST_PROTOCOL)
            return -EINVAL;

      alts = usblp->protocol[protocol].alt_setting;
      if (alts < 0)
            return -EINVAL;
      r = usb_set_interface(usblp->dev, usblp->ifnum, alts);
      if (r < 0) {
            printk(KERN_ERR "usblp: can't set desired altsetting %d on interface %d\n",
                  alts, usblp->ifnum);
            return r;
      }

      usblp->bidir = (usblp->protocol[protocol].epread != NULL);
      usblp->current_protocol = protocol;
      dbg("usblp%d set protocol %d", usblp->minor, protocol);
      return 0;
}

/* Retrieves and caches device ID string.
 * Returns length, including length bytes but not null terminator.
 * On error, returns a negative errno value. */
static int usblp_cache_device_id_string(struct usblp *usblp)
{
      int err, length;

      err = usblp_get_id(usblp, 0, usblp->device_id_string, USBLP_DEVICE_ID_SIZE - 1);
      if (err < 0) {
            dbg("usblp%d: error = %d reading IEEE-1284 Device ID string",
                  usblp->minor, err);
            usblp->device_id_string[0] = usblp->device_id_string[1] = '\0';
            return -EIO;
      }

      /* First two bytes are length in big-endian.
       * They count themselves, and we copy them into
       * the user's buffer. */
      length = be16_to_cpu(*((__be16 *)usblp->device_id_string));
      if (length < 2)
            length = 2;
      else if (length >= USBLP_DEVICE_ID_SIZE)
            length = USBLP_DEVICE_ID_SIZE - 1;
      usblp->device_id_string[length] = '\0';

      dbg("usblp%d Device ID string [len=%d]=\"%s\"",
            usblp->minor, length, &usblp->device_id_string[2]);

      return length;
}

static void usblp_disconnect(struct usb_interface *intf)
{
      struct usblp *usblp = usb_get_intfdata (intf);

      usb_deregister_dev(intf, &usblp_class);

      if (!usblp || !usblp->dev) {
            err("bogus disconnect");
            BUG ();
      }

      device_remove_file(&intf->dev, &dev_attr_ieee1284_id);

      mutex_lock (&usblp_mutex);
      mutex_lock (&usblp->mut);
      usblp->present = 0;
      wake_up(&usblp->wwait);
      wake_up(&usblp->rwait);
      usb_set_intfdata (intf, NULL);

      usblp_unlink_urbs(usblp);
      mutex_unlock (&usblp->mut);

      if (!usblp->used)
            usblp_cleanup (usblp);
      mutex_unlock (&usblp_mutex);
}

static int usblp_suspend (struct usb_interface *intf, pm_message_t message)
{
      struct usblp *usblp = usb_get_intfdata (intf);

      /* we take no more IO */
      usblp->sleeping = 1;
      usblp_unlink_urbs(usblp);
#if 0 /* XXX Do we want this? What if someone is reading, should we fail? */
      /* not strictly necessary, but just in case */
      wake_up(&usblp->wwait);
      wake_up(&usblp->rwait);
#endif

      return 0;
}

static int usblp_resume (struct usb_interface *intf)
{
      struct usblp *usblp = usb_get_intfdata (intf);
      int r;

      usblp->sleeping = 0;
      r = handle_bidir (usblp);

      return r;
}

static struct usb_device_id usblp_ids [] = {
      { USB_DEVICE_INFO(7, 1, 1) },
      { USB_DEVICE_INFO(7, 1, 2) },
      { USB_DEVICE_INFO(7, 1, 3) },
      { 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 */
};

MODULE_DEVICE_TABLE (usb, usblp_ids);

static struct usb_driver usblp_driver = {
      .name =           "usblp",
      .probe =    usblp_probe,
      .disconnect =     usblp_disconnect,
      .suspend =  usblp_suspend,
      .resume =   usblp_resume,
      .id_table = usblp_ids,
      .supports_autosuspend = 1,
};

static int __init usblp_init(void)
{
      return usb_register(&usblp_driver);
}

static void __exit usblp_exit(void)
{
      usb_deregister(&usblp_driver);
}

module_init(usblp_init);
module_exit(usblp_exit);

MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
module_param(proto_bias, int, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(proto_bias, "Favourite protocol number");
MODULE_LICENSE("GPL");

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