Fix new kernel-doc warnings in usb core:
Warning(drivers/usb/core/usb.c:79): No description found for parameter 'config'
Warning(drivers/usb/core/usb.c:79): No description found for parameter 'iface_num'
Warning(drivers/usb/core/usb.c:79): No description found for parameter 'alt_num'
Warning(drivers/usb/core/hcd.c:1622): No description found for parameter 'udev'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1315) fixes some bugs in the USB core authorization
code:
usb_deauthorize_device() should deallocate the device strings
instead of leaking them, and it should invoke
usb_destroy_configuration() (which does proper reference
counting) instead of freeing the config information directly.
usb_authorize_device() shouldn't change the device strings
until it knows that the authorization will succeed, and it should
autosuspend the device at the end (having autoresumed the
device at the start).
Because the device strings can be changed, the sysfs routines
to display the strings must protect the string pointers by
locking the device.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Acked-by: David Vrabel <david.vrabel@csr.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1314) renames usb_configure_device() and
usb_configure_device_otg() in the hub driver. Neither name is
appropriate because these routines enumerate devices, they don't
configure them. That's handled by usb_choose_configuration() and
usb_set_configuration().
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
USB drivers that create character devices call usb_register_dev in their
probe function. This associates the usb_interface device with that minor
number and creates the character device and announces it to the world.
However, the driver's probe function is called before the new
usb_interface is added to the driver's klist_devices.
This is a problem because userspace will respond to the character device
creation announcement by opening the character device. The driver's open
function will the call usb_find_interface to find the usb_interface
associated with that minor number. usb_find_interface will walk the
driver's list of devices and find the usb_interface with the matching
minor number.
Because the announcement happens before the usb_interface is added to the
driver's klist_devices, a race condition exists. A straightforward fix
is to walk the list of devices on usb_bus_type instead since the device
is added to that list before the announcement occurs.
bus_find_device calls get_device to bump the reference count on the found
device. It is arguable that the reference count should be dropped by the
caller of usb_find_interface instead of usb_find_interface, however,
the current users of usb_find_interface do not expect this.
The original version of this patch only matched against minor number
instead of driver and minor number. This version matches against both.
Signed-off-by: Russ Dill <Russ.Dill@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit a2582bd478.
It turned out to be buggy and broke USB printers from working.
Cc: Russ Dill <Russ.Dill@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix the following sparse warning:
drivers/usb/core/message.c:1583:6: warning: symbol '__usb_queue_reset_device' was not declared. Should it be static?
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix the following sparse warning:
drivers/usb/core/hub.c:1664:37: warning: Using plain integer as NULL pointer
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Fix the following sparse warning:
drivers/usb/core/usb.c:1033:15: warning: symbol 'usb_debug_devices' was not declared. Should it be static?
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Make the USB core check the bandwidth when switching from one
interface alternate setting to another. Also check the bandwidth
when resetting a configuration (so that alt setting 0 is used). If
this check fails, the device's state is unchanged. If the device
refuses the new alt setting, re-instate the old alt setting in the
host controller hardware.
If a USB device doesn't have an alternate interface setting 0, install
the first alt setting in its descriptors when a new configuration is
requested, or the device is reset.
Add a mutex per root hub to protect bandwidth operations:
adding/reseting/changing configurations, and changing alternate interface
settings. We want to ensure that the xHCI host controller and the USB
device are set up for the same configurations and alternate settings.
There are two (possibly three) steps to do this:
1. The host controller needs to check that bandwidth is available for a
different setting, by issuing and waiting for a configure endpoint
command.
2. Once that returns successfully, a control message is sent to the
device.
3. If that fails, the host controller must be notified through another
configure endpoint command.
The mutex is used to make these three operations seem atomic, to prevent
another driver from using more bandwidth for a different device while
we're in the middle of these operations.
While we're touching the bandwidth code, rename usb_hcd_check_bandwidth()
to usb_hcd_alloc_bandwidth(). This function does more than just check
that the bandwidth change won't exceed the bus bandwidth; it actually
changes the bandwidth configuration in the xHCI host controller.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Refactor out the code to find alternate interface settings into
usb_find_alt_setting(). Print a debugging message and return null if the
alt setting is not found.
While we're at it, correct a bug in the refactored code. The interfaces
in the configuration's interface cache are not necessarily in numerical
order, so we can't just use the interface number as an array index. Loop
through the interface caches, looking for the correct interface.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Accroding commit 0994375e, which is adding remove_id sysfs attr
for pci drivers, for management tools dynamically bind/unbind
a pci/usb devices to a specified drivers; with this patch,
the management tools can be simplied.
And the original code didn't handle the failure of
usb_create_newid_file, fixed in this patch.
Signed-off-by: CHENG Renquan <rqcheng@smu.edu.sg>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1303) revises the USB Power Management infrastructure to
make it compatible with the new driver-model Runtime PM framework:
Drivers are no longer allowed to access intf->pm_usage_cnt
directly; the PM framework manages its own usage counters.
usb_autopm_set_interface() is eliminated, because it directly
sets intf->pm_usage_cnt.
usb_autopm_enable() and usb_autopm_disable() are eliminated,
because they call usb_autopm_set_interface().
usb_autopm_get_interface_no_resume() and
usb_autopm_put_interface_no_suspend() are added. They
correspond to pm_runtime_get_noresume() and
pm_runtime_put_noidle() in the PM framework.
The power/level attribute no longer accepts "suspend", only
"on" and "auto". The PM framework doesn't allow devices to be
forced into a suspended mode.
The hub driver contains the only code that violates the new
guidelines. It is updated to use the new interface routines instead.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This is not exported from the usb core, yet we rely on it to create
paths to interfaces for this device in sysfs. Export it to make
userspace tools have an easier time to figure things out.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a missing goto. We dereference usb_class on the next line.
Found by smatch static checker.
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1302) removes the auto_pm flag from struct usb_device.
The flag's only purpose was to distinguish between autosuspends and
external suspends, but that information is now available in the
pm_message_t argument passed to suspend methods.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Quiet the following sparse noise:
warning: Using plain integer as NULL pointer
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
USB drivers that create character devices call usb_register_dev in their
probe function. This associates the usb_interface device with that minor
number and creates the character device and announces it to the world.
However, the driver's probe function is called before the new
usb_interface is added to the driver's klist_devices.
This is a problem because userspace will respond to the character device
creation announcement by opening the character device. The driver's open
function will the call usb_find_interface to find the usb_interface
associated with that minor number. usb_find_interface will walk the
driver's list of devices and find the usb_interface with the matching
minor number.
Because the announcement happens before the usb_interface is added to the
driver's klist_devices, a race condition exists. A straightforward fix
is to walk the list of devices on usb_bus_type instead since the device
is added to that list before the announcement occurs.
bus_find_device calls get_device to bump the reference count on the found
device. It is arguable that the reference count should be dropped by the
caller of usb_find_interface instead of usb_find_interface, however,
the current users of usb_find_interface do not expect this.
Signed-off-by: Russ Dill <Russ.Dill@gmail.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
In map_urb_for_dma(), the DMA address returned by dma_map_single()
is not checked to determine if it is legal. This lack of checking
contributed to a problem with the libertas wireless driver
(http://marc.info/?l=linux-wireless&m=125695331205062&w=2). The
difficulty was not detected until the buffer was unmapped. By this time
memory corruption had occurred.
The situation is fixed by testing the returned DMA address, and
returning -EAGAIN if the address is invalid.
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1298) fixes a bug in the new scatter-gather URB
facility. If an URB uses a scatterlist then it should not have the
URB_NO_INTERRUPT flag set; otherwise the system won't be notified when
the transfer completes.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Vrabel <david.vrabel@csr.com>
CC: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1297) adds a "remove" attribute to each USB device's
directory in sysfs. Writing to this attribute causes the device to be
deconfigured (the same as writing 0 to the "bConfigurationValue"
attribute) and then tells the hub driver to disable the device's
upstream port. The device remains locked during these activities so
there is no possibility of it getting reconfigured in between. The
port will remain disabled until after the device is unplugged.
The purpose of this is to provide a means for user programs to imitate
the "Safely remove hardware" applet in Windows. Some devices do
expect their ports to be disabled before they are unplugged, and they
provide visual feedback to users indicating when they can safely be
unplugged.
The security implications are minimal. Writing to the "remove"
attribute is no more dangerous than writing to the
"bConfigurationValue" attribute.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: David Zeuthen <davidz@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1296) gets rid of the fixed DMA-buffer mapping used by
the hub driver for its status URB. This URB doesn't get used much --
mainly when a device is plugged in or unplugged -- so the dynamic
mapping overhead is minimal. And most systems have many fewer
external hubs than root hubs, which don't need a mapped buffer anyway.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb: better error handling in usb_port_suspend
- disable remote wakeup only if it was enabled
- refuse to autosuspend if remote wakeup fails to be enabled
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Check urb->interval on interrupt transfers and allow those with valid
values (6 <= interval <= 16).
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The WHCI HCD will also support urbs with scatter-gather lists. Add a
usb_bus field to indicated how many sg list elements are supported by
the HCD. Use this to decide whether to pass the scatter-list to the HCD
or not.
Make the usb-storage driver use this new field.
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Matthew Dharm <mdharm-usb@one-eyed-alien.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Knowing which configuration was chosen is a debugging aid more than it
is informational.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Half the compat_ioctl handling is in devio.c, the other
half is in fs/compat_ioctl.c. This moves everything into
one place for consistency.
As a positive side-effect, push down the BKL into the
ioctl methods.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Alon Bar-Lev <alon.barlev@gmail.com>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: linux-usb@vger.kernel.org
This patch (as1304) fixes a regression in ehci-hcd. Evidently some
hubs don't handle Clear-TT-Buffer requests correctly, so we should
avoid sending them when they don't appear to be absolutely necessary.
The reported symptom is that output on a downstream audio device cuts
out because the hub stops relaying isochronous packets.
The patch prevents Clear-TT-Buffer requests from being sent following
a STALL handshake. In theory a STALL indicates either that the
downstream device sent a STALL or that no matching TT buffer could be
found. In either case, the transfer is completed and the TT buffer
does not remain busy, so it doesn't need to be cleared.
Also, the patch fixes a minor flaw in the code that actually sends the
Clear-TT-Buffer requests. Although the pipe direction isn't really
used for control transfers, it should be a Send rather than a Receive.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Javier Kohen <jkohen@users.sourceforge.net>
CC: David Brownell <david-b@pacbell.net>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Add a hook for updating xHCI internal structures after khubd fetches the
hub descriptor and sets up the hub's TT information. The xHCI driver must
update the internal structures before devices under the hub can be
enumerated.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The xHCI driver needs to set the route string in the slot context of all
devices, not just SuperSpeed devices. The route string concept was added
in the USB 3.0 specification, section 10.1.3.2. Each hub in the topology
is expected to have no more than 15 ports in order for the route string of
a device to be unique. SuperSpeed hubs are restricted to only having 15
ports, but FS/LS/HS hubs are not. The xHCI specification says that if the
port number the device is under is greater than 15, that portion of the
route string shall be set to 15.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb: check for IO errors usb_set_interface can return
if they happen while unbinding a flag is set to retry upon probe
if they happen during probe they are handled as probe errors
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1283) adds a new flag, USBDEVFS_URB_BULK_CONTINUATION,
to usbfs. It is intended for userspace libraries such as libusb and
openusb. When they have to break up a single usbfs bulk transfer into
multiple URBs, they will set the flag on all but the first URB of the
series.
If an error other than an unlink occurs, the kernel will automatically
cancel all the following URBs for the same endpoint and refuse to
accept new submissions, until an URB is encountered that is not marked
as a BULK_CONTINUATION. Such an URB would indicate the start of a new
transfer or the presence of an older library, so the kernel returns to
normal operation.
This enables libraries to delimit bulk transfers correctly, even in
the presence of early termination as indicated by short packets.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The previous code had a bug that would add a trailing null byte to
the returned descriptor.
Signed-off-by: George Spelvin <linux@horizon.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
usb_buffer_map_sg should return negative on error according to
its documentation. But dma_map_sg returns 0 on error. Take this
into account and return -ENOMEM in such situation.
While at it, return -EINVAL instead of -1 when wrong input is
passed in.
If this wasn't done, usb_sg_* operations used after usb_sg_init
which returned 0 may cause oopses/deadlocks since we don't init
structures/entries, esp. completion and status entry.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The current limit only allows isochronous transfers up to 32kbyte/urb,
updating this to 192 kbyte/urb improves the reliability of the
transfer. USB 2.0 transfer is possible with 32kbyte but increases the
chance of corrupted/incomplete data when the system is performing some
other tasks in the background.
http://www.spinics.net/lists/linux-usb/msg19955.html
Signed-off-by: Markus Rechberger <mrechberger@gmail.com>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1268) changes the way usbcore handles child devices that
undergo a disconnection and reconnection while the parent hub is
suspended. Currently, if the child isn't enabled for remote wakeup we
leave it alone, figuring that it will go through a reset-resume when
somebody tries to use it.
However this isn't a good approach if the reason for the disconnection
is that the child decided to switch modes or in some other way alter
its descriptors. In that case we want to re-enumerate it as soon as
possible, not wait until somebody forces a reset-resume.
To resolve the issue, this patch treats reconnected suspended child
devices as though they had requested a remote wakeup, even if they
weren't enabled for it. The mode switch or descriptor change will be
detected during the reset part of the reset-resume, and the device
will be re-enumerated immediately.
The disadvantage of this change is that it will cause autosuspended
devices to be resumed when the computer wakes up from a system sleep
during which the root hub was reset or lost power. This shouldn't
matter much; some people would even argue that autosuspended devices
should _always_ be resumed when the system wakes up!
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: "Yang Fei-AFY095" <fei.yang@motorola.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1267) changes usb_kick_khubd() and hdev_to_hub() to make
them more resilient against situations where a hub device isn't bound
to the hub driver. The code assumes that if a root hub was
successfully registered then it must be bound to the hub driver.
But this assumption can fail if the user manually unbinds the hub
driver, or more importantly, if the host controller dies causing
usb_set_configuration to fail.
To protect against these possibilities, make hdev_to_hub() check that
the hub device is configured before dereferencing the active
configuration, and make usb_kick_khubd() check that the pointer to the
hub's private data structure isn't NULL.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1261) reduces the amount of detailed URB information
logged by usbfs when the usbfs_snoop parameter is enabled.
Currently we don't display the final status value for a completed URB.
But we do display the entire data buffer twice: both before submission
and after completion. The after-completion display doesn't limit
itself to the actual_length value. But since usbmon is readily
available in virtually all distributions, there's no reason for usbfs
to print out any buffer contents at all!
So this patch restricts the information to: userspace buffer pointer,
endpoint number, type, and direction, length or actual_length, and
timeout value or status. Now everything fits neatly into a single
line.
Along with those changes, the patch also fixes the snoop output for
the REAPURBNDELAY and REAPURBNDELAY32 ioctls. The current version
omits the 'N' from the names.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1260) changes the pm_usage_cnt field in struct
usb_interface from an int to an atomic_t. This is so that drivers can
invoke the usb_autopm_get_interface_async() and
usb_autopm_put_interface_async() routines without locking and without
fear of corrupting the pm_usage_cnt value.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1258) implements a feature that users have been asking
for: It gives programs the ability to "claim" a port on a hub, via a
new usbfs ioctl. A device plugged into a "claimed" port will not be
touched by the kernel beyond the immediate necessities of
initialization and enumeration.
In particular, when a device is plugged into a "claimed" port, the
kernel will not select and install a configuration. And when a config
is installed by usbfs or sysfs, the kernel will not probe any drivers
for any of the interfaces. (However the kernel will fetch various
string descriptors during enumeration. One could argue that this
isn't really necessary, but the strings are exported in sysfs.)
The patch does not guarantee exclusive access to these devices; it is
still possible for more than one program to open the device file
concurrently. Programs are responsible for coordinating access among
themselves.
A demonstration program showing how to use the new interface can be
found in an attachment to
http://marc.info/?l=linux-usb&m=124345857431452&w=2
The patch also makes a small simplification to the hub driver,
replacing a bunch of more-or-less useless variants of "out of memory"
with a single message.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This fix permits the "new" usbmon to access usb-storage's data buffer
without DMA remapping tricks. It should be compatible with PIO controllers
and not add any new crashes. Note that from now on PIO controllers and
usbmon are uniform in their access pattern and if one crashes then
the other will too. Hopefuly neither does.
As a side effect, we get rid for #ifdefs, which were a little ugly.
Signed-off-by: Pete Zaitcev <zaitcev@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
When there's a descriptor after the SuperSpeed endpoint companion
descriptor, the previous code would have skipped over twice the length it
was supposed to. This code fixes crashes seen with UASP devices (which
have a UASP descriptor after the SS endpoint companion descriptor).
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This allows subsytems to provide devtmpfs with non-default permissions
for the device node. Instead of the default mode of 0600, null, zero,
random, urandom, full, tty, ptmx now have a mode of 0666, which allows
non-privileged processes to access standard device nodes in case no
other userspace process applies the expected permissions.
This also fixes a wrong assignment in pktcdvd and a checkpatch.pl complain.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Let attribute group vectors be declared "const". We'd
like to let most attribute metadata live in read-only
sections... this is a start.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1272) changes the error code returned when an open call
for a USB device node fails to locate the corresponding device. The
appropriate error code is -ENODEV, not -ENOENT.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Kay Sievers <kay.sievers@vrfy.org>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
