Unfortunately, usb_set_configuration() is widely mis-used as a
lightweight device reset.  That's trouble because setting a
configuration must sometimes involve things that don't relate
at all to a light reset, and can't be done in contexts like
driver probe() calls.

This patch updates most usb_set_configuration() users to use a call
that provides more appropriate functionality:

 - Adds a new usb_reset_configuration() call, which never needs
   to change very much usbcore state.

 - Uses it to replace most usb_set_configuration() calls, in
   many serial drivers, hisax, dvb, irda, and so on.

 - Modifies usb_reset_device() so it issues the control request
   directly.  It's both more of a reset (hides a USB reset) and
   less of one (altsettings are unchanged).

- Makes usbfs return the error code instead of discarding it.

Once this goes in, then usb_set_configuration() can be made to
work properly (including from sysfs).

Unfortunately I can't test this change (beyond compilation),
since I don't have any of these devices.  Please verify that
this works, and merge if it does.

- Dave

--- 1.33/drivers/usb/core/message.c     Fri Aug  1 05:03:12 2003
+++ edited/drivers/usb/core/message.c   Mon Aug 11 14:56:25 2003
@@ -964,6 +964,55 @@
 }
 
 /**
+ * usb_reset_configuration - lightweight device reset
+ * @dev: the device whose configuration is being reset
+ *
+ * This issues a standard SET_CONFIGURATION request to the device using
+ * the current configuration.  The effect is to reset most USB-related
+ * state in the device, including interface altsettings (reset to zero),
+ * endpoint halts (cleared), and data toggle (only for bulk and interrupt
+ * endpoints).  Other usbcore state is unchanged, including bindings of
+ * usb device drivers to interfaces.
+ *
+ * Because this affects multiple interfaces, avoid using this with composite
+ * (multi-interface) devices.  Instead, the driver for each interface may
+ * use usb_set_interface() on the interfaces it claims.  Resetting the whole
+ * configuration would affect other drivers' interfaces.
+ *
+ * Returns zero on success, else a negative error code.
+ */
+int usb_reset_configuration(struct usb_device *dev)
+{
+       int                     i, retval;
+       struct usb_host_config  *config;
+
+       for (i = 1; i < 16; ++i) {
+               usb_disable_endpoint(dev, i);
+               usb_disable_endpoint(dev, i + USB_DIR_IN);
+       }
+
+       config = dev->actconfig;
+       retval = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+                       USB_REQ_SET_CONFIGURATION, 0,
+                       config->desc.bConfigurationValue, 0,
+                       NULL, 0, HZ * USB_CTRL_SET_TIMEOUT);
+       if (retval < 0)
+               return retval;
+
+       dev->toggle[0] = dev->toggle[1] = 0;
+       dev->halted[0] = dev->halted[1] = 0;
+
+       /* re-init hc/hcd interface/endpoint state */
+       for (i = 0; i < config->desc.bNumInterfaces; i++) {
+               struct usb_interface *intf = config->interface[i];
+
+               intf->act_altsetting = 0;
+               usb_enable_interface(dev, intf);
+       }
+       return 0;
+}
+
+/**
  * usb_set_configuration - Makes a particular device setting be current
  * @dev: the device whose configuration is being updated
  * @configuration: the configuration being chosen.
@@ -1136,7 +1185,10 @@
 EXPORT_SYMBOL(usb_get_status);
 EXPORT_SYMBOL(usb_get_string);
 EXPORT_SYMBOL(usb_string);
+
+// synchronous calls that also maintain usbcore state
 EXPORT_SYMBOL(usb_clear_halt);
+EXPORT_SYMBOL(usb_reset_configuration);
 EXPORT_SYMBOL(usb_set_configuration);
 EXPORT_SYMBOL(usb_set_interface);
 
--- 1.18/drivers/isdn/hisax/st5481_usb.c        Sat Aug  9 05:19:09 2003
+++ edited/drivers/isdn/hisax/st5481_usb.c      Mon Aug 11 14:56:55 2003
@@ -252,8 +252,8 @@
        
        DBG(1,"");
        
-       if ((status = usb_set_configuration 
(dev,dev->config[0].desc.bConfigurationValue)) < 0) {
-               WARN("set_configuration failed,status=%d",status);
+       if ((status = usb_reset_configuration (dev)) < 0) {
+               WARN("reset_configuration failed,status=%d",status);
                return status;
        }
 
--- 1.2/drivers/media/dvb/ttusb-budget/dvb-ttusb-budget.c       Wed Aug  6 14:06:39 
2003
+++ edited/drivers/media/dvb/ttusb-budget/dvb-ttusb-budget.c    Mon Aug 11 14:56:25 
2003
@@ -1017,7 +1017,7 @@
 
 static int ttusb_setup_interfaces(struct ttusb *ttusb)
 {
-       usb_set_configuration(ttusb->dev, 1);
+       usb_reset_configuration(ttusb->dev);
        usb_set_interface(ttusb->dev, 1, 1);
 
        ttusb->bulk_out_pipe = usb_sndbulkpipe(ttusb->dev, 1);
--- 1.42/drivers/net/irda/irda-usb.c    Tue Aug  5 08:25:31 2003
+++ edited/drivers/net/irda/irda-usb.c  Mon Aug 11 14:56:25 2003
@@ -1482,9 +1482,9 @@
                goto err_out_2;
        }
 
-       /* Is this really necessary? */
-       if (usb_set_configuration (dev, dev->config[0].desc.bConfigurationValue) < 0) {
-               err("set_configuration failed");
+       /* Is this really necessary? (no, except maybe for broken devices) */
+       if (usb_reset_configuration (dev) < 0) {
+               err("reset_configuration failed");
                ret = -EIO;
                goto err_out_3;
        }
--- 1.48/drivers/usb/class/cdc-acm.c    Tue Jul 29 04:28:54 2003
+++ edited/drivers/usb/class/cdc-acm.c  Mon Aug 11 14:56:25 2003
@@ -593,7 +593,14 @@
                                epwrite = &ifdata->endpoint[0].desc;
                        }
 
-                       usb_set_configuration(dev, cfacm->desc.bConfigurationValue);
+                       /* FIXME don't scan every config. it's either correct
+                        * when we probe(), or some other task must fix this.
+                        */
+                       if (dev->actconfig != cfacm) {
+                               err("need inactive config #%d",
+                                       cfacm->desc.bConfigurationValue);
+                               return -ENODEV;
+                       }
 
                        for (minor = 0; minor < ACM_TTY_MINORS && acm_table[minor]; 
minor++);
                        if (acm_table[minor]) {
--- 1.52/drivers/usb/core/devio.c       Thu Jul 31 09:22:43 2003
+++ edited/drivers/usb/core/devio.c     Mon Aug 11 14:56:25 2003
@@ -762,9 +762,7 @@
 
        if (get_user(u, (unsigned int __user *)arg))
                return -EFAULT;
-       if (usb_set_configuration(ps->dev, u) < 0)
-               return -EINVAL;
-       return 0;
+       return usb_set_configuration(ps->dev, u);
 }
 
 static int proc_submiturb(struct dev_state *ps, void __user *arg)
--- 1.76/drivers/usb/core/hub.c Wed Aug  6 04:52:20 2003
+++ edited/drivers/usb/core/hub.c       Mon Aug 11 14:56:25 2003
@@ -1335,7 +1335,10 @@
 
        kfree(descriptor);
 
-       ret = usb_set_configuration(dev, dev->actconfig->desc.bConfigurationValue);
+       ret = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
+                       USB_REQ_SET_CONFIGURATION, 0,
+                       dev->actconfig->desc.bConfigurationValue, 0,
+                       NULL, 0, HZ * USB_CTRL_SET_TIMEOUT);
        if (ret < 0) {
                err("failed to set dev %s active configuration (error=%d)",
                        dev->devpath, ret);
--- 1.30/drivers/usb/media/dabusb.c     Wed Jul 16 13:55:43 2003
+++ edited/drivers/usb/media/dabusb.c   Mon Aug 11 14:56:25 2003
@@ -747,8 +747,8 @@
        s->usbdev = usbdev;
        s->devnum = intf->minor;
 
-       if (usb_set_configuration (usbdev, usbdev->config[0].desc.bConfigurationValue) 
< 0) {
-               err("set_configuration failed");
+       if (usb_reset_configuration (usbdev) < 0) {
+               err("reset_configuration failed");
                goto reject;
        }
        if (usbdev->descriptor.idProduct == 0x2131) {
--- 1.27/drivers/usb/media/stv680.c     Thu May 29 13:30:29 2003
+++ edited/drivers/usb/media/stv680.c   Mon Aug 11 14:56:25 2003
@@ -225,8 +225,9 @@
 static int stv_set_config (struct usb_stv *dev, int configuration, int interface, int 
alternate)
 {
 
-       if (usb_set_configuration (dev->udev, configuration) < 0) {
-               PDEBUG (1, "STV(e): FAILED to set configuration %i", configuration);
+       if (configuration != dev->udev->actconfig->desc.bConfigurationValue
+                       || usb_reset_configuration (dev->udev) < 0) {
+               PDEBUG (1, "STV(e): FAILED to reset configuration %i", configuration);
                return -1;
        }
        if (usb_set_interface (dev->udev, interface, alternate) < 0) {
--- 1.20/drivers/usb/misc/tiglusb.c     Tue Jun 17 08:12:48 2003
+++ edited/drivers/usb/misc/tiglusb.c   Mon Aug 11 14:56:25 2003
@@ -57,7 +57,7 @@
 static inline int
 clear_device (struct usb_device *dev)
 {
-       if (usb_set_configuration (dev, dev->config[0].desc.bConfigurationValue) < 0) {
+       if (usb_reset_configuration (dev) < 0) {
                err ("clear_device failed");
                return -1;
        }
@@ -343,8 +343,10 @@
            && (dev->descriptor.idVendor != 0x451))
                return -ENODEV;
 
-       if (usb_set_configuration (dev, dev->config[0].desc.bConfigurationValue) < 0) {
-               err ("tiglusb_probe: set_configuration failed");
+       // NOTE:  it's already in this config, this shouldn't be needed.
+       // is this working around some hardware bug?
+       if (usb_reset_configuration (dev) < 0) {
+               err ("tiglusb_probe: reset_configuration failed");
                return -ENODEV;
        }
 
--- 1.39/drivers/usb/serial/empeg.c     Wed Jun  4 03:57:48 2003
+++ edited/drivers/usb/serial/empeg.c   Mon Aug 11 14:56:25 2003
@@ -464,8 +464,13 @@
 
        dbg("%s", __FUNCTION__);
 
-       dbg("%s - Set config to 1", __FUNCTION__);
-       r = usb_set_configuration (serial->dev, 1);
+       if (serial->dev->actconfig->desc.bConfigurationValue != 1) {
+               err("active config #%d != 1 ??",
+                       serial->dev->actconfig->desc.bConfigurationValue);
+               return -ENODEV;
+       }
+       dbg("%s - reset config", __FUNCTION__);
+       r = usb_reset_configuration (serial->dev);
 
        /* continue on with initialization */
        return r;
--- 1.31/drivers/usb/serial/ipaq.c      Sat Jul 12 03:25:54 2003
+++ edited/drivers/usb/serial/ipaq.c    Mon Aug 11 14:56:25 2003
@@ -555,8 +555,12 @@
 static int ipaq_startup(struct usb_serial *serial)
 {
        dbg("%s", __FUNCTION__);
-       usb_set_configuration(serial->dev, 1);
-       return 0;
+       if (serial->dev->actconfig->desc.bConfigurationValue != 1) {
+               err("active config #%d != 1 ??",
+                       serial->dev->actconfig->desc.bConfigurationValue);
+               return -ENODEV;
+       }
+       return usb_reset_configuration (serial->dev);
 }
 
 static void ipaq_shutdown(struct usb_serial *serial)
--- 1.66/drivers/usb/serial/visor.c     Fri Aug  1 09:26:32 2003
+++ edited/drivers/usb/serial/visor.c   Mon Aug 11 14:56:25 2003
@@ -763,8 +763,14 @@
 
        dbg("%s", __FUNCTION__);
 
-       dbg("%s - Set config to 1", __FUNCTION__);
-       usb_set_configuration (serial->dev, 1);
+       if (serial->dev->actconfig->desc.bConfigurationValue != 1) {
+               err("active config #%d != 1 ??",
+                       serial->dev->actconfig->desc.bConfigurationValue);
+               return -ENODEV;
+       }
+       dbg("%s - reset config", __FUNCTION__);
+       retval = usb_reset_configuration (serial->dev);
+
 
        if (id->driver_info) {
                startup = (void *)id->driver_info;
--- 1.74/drivers/usb/storage/usb.c      Sun Jul  6 11:14:28 2003
+++ edited/drivers/usb/storage/usb.c    Mon Aug 11 14:56:25 2003
@@ -921,9 +921,14 @@
        if (us->protocol == US_PR_EUSB_SDDR09 ||
                        us->protocol == US_PR_DPCM_USB) {
                /* set the configuration -- STALL is an acceptable response here */
-               result = usb_set_configuration(us->pusb_dev, 1);
+               if (us->pusb_dev->actconfig->desc.bConfigurationValue != 1) {
+                       US_DEBUGP("active config #%d != 1 ??\n", us->pusb_dev
+                               ->actconfig->desc.bConfigurationValue);
+                       goto BadDevice;
+               }
+               result = usb_reset_configuration(us->pusb_dev);
 
-               US_DEBUGP("Result from usb_set_configuration is %d\n", result);
+               US_DEBUGP("Result of usb_reset_configuration is %d\n", result);
                if (result == -EPIPE) {
                        US_DEBUGP("-- stall on control interface\n");
                } else if (result != 0) {
--- 1.84/include/linux/usb.h    Thu Jul 31 09:22:43 2003
+++ edited/include/linux/usb.h  Mon Aug 11 14:56:25 2003
@@ -869,6 +869,7 @@
 
 /* wrappers that also update important state inside usbcore */
 extern int usb_clear_halt(struct usb_device *dev, int pipe);
+extern int usb_reset_configuration(struct usb_device *dev);
 extern int usb_set_configuration(struct usb_device *dev, int configuration);
 extern int usb_set_interface(struct usb_device *dev, int ifnum, int alternate);
 
--- 1.43/sound/usb/usbaudio.c   Fri Aug  1 10:52:20 2003
+++ edited/sound/usb/usbaudio.c Mon Aug 11 14:56:25 2003
@@ -2560,8 +2560,8 @@
                err = usb_get_device_descriptor(dev);
                config = dev->actconfig;
                if (err < 0) snd_printdd("error usb_get_device_descriptor: %d\n", err);
-               err = usb_set_configuration(dev, 
get_cfg_desc(config)->bConfigurationValue);
-               if (err < 0) snd_printdd("error usb_set_configuration: %d\n", err);
+               err = usb_reset_configuration(dev);
+               if (err < 0) snd_printdd("error usb_reset_configuration: %d\n", err);
                snd_printdd("extigy_boot: new boot length = %d\n", 
get_cfg_desc(config)->wTotalLength);
                return -ENODEV; /* quit this anyway */
        }
@@ -2761,8 +2761,8 @@
                 * now look for an empty slot and create a new card instance
                 */
                /* first, set the current configuration for this device */
-               if (usb_set_configuration(dev, 
get_cfg_desc(config)->bConfigurationValue) < 0) {
-                       snd_printk(KERN_ERR "cannot set configuration (value 0x%x)\n", 
get_cfg_desc(config)->bConfigurationValue);
+               if (usb_reset_configuration(dev) < 0) {
+                       snd_printk(KERN_ERR "cannot reset configuration (value 
0x%x)\n", get_cfg_desc(config)->bConfigurationValue);
                        goto __error;
                }
                for (i = 0; i < SNDRV_CARDS; i++)

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