This patch (as1153) fixes a potential problem in hub initialization.
Starting in 2.6.28, initialization was split into several tasks to
help speed up booting. This opens the possibility that the hub may be
autosuspended before all the initialization tasks can complete.
Normally that wouldn't matter, but with incomplete initialization
there is a risk that the hub would never autoresume -- especially if
devices were plugged into the hub beforehand. The solution is a
simple one-line change to suppress autosuspend until the
initialization is finished.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1151) protects usbcore against drivers that try to
unlink an URB after the URB's device or bus have been removed. The
core does not currently check for this, and certain drivers can cause
a crash if they are running while an HCD is unloaded.
Certainly it would be best to fix the guilty drivers. But a little
defensive programming doesn't hurt, especially since it appears that
quite a few drivers need to be fixed.
The patch prevents the problem by grabbing a reference to the device
while an unlink is in progress and using a new spinlock to synchronize
unlinks with device removal. (There's no need to acquire a reference
to the bus as well, since the device structure itself keeps a
reference to the bus.) In addition, the kerneldoc is updated to
indicate that URBs should not be unlinked after the disconnect method
returns.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1152) may help prevent some problems associated with the
new policy of unbinding drivers that don't support suspend/resume or
pre_reset/post_reset. If for any reason the resume or reset fails, and
the device is logically disconnected, there's no point in trying to
rebind the driver. So the patch checks for success before carrying
out the unbind/rebind.
There was a report from one user that this fixed a problem he was
experiencing, but the details never became fully clear. In any case,
adding these tests can't hurt.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch adds initial_descriptor_timeout module parameter for usbcore.ko
to allow modify initial 64-byte USB_REQ_GET_DESCRIPTOR timeout for
non-standard devices.
For example, the SATA8000 device from DATAST0R Technology Corp
requires about 10 seconds to send reply (probably it waits until
inserted disk is ready for operation).
Also, this patch adds missing usbcore parameters to
Documentation/kernel-parameters.txt.
Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1137) changes the hub_activate() routine, replacing the
power-power-up and debounce delays with delayed_work calls. The idea
is that on systems where the USB stack is compiled into the kernel
rather than built as modules, these delays will no longer block the
boot thread. At least 100 ms is saved for each root hub, which can
add up to a significant savings in total boot time.
Arjan van de Ven was very pleased to see that this shaved 700 ms off
his computer's boot time. Since his total boot time is on the order
of two seconds, the improvement is considerable.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Arjan van de Ven <arjan@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1135) essentially reverts the major parts of two earlier
patches to usbcore, because they ended up causing a regression.
Trying to recover from transient communication errors can lead to
other problems, because operations that failed during the error period
are not always retried. The simplest example is the initial
Set-Config request sent after device enumeration; if it gets lost then
it will not be retried and the device will remain unconfigured.
This patch restores the old behavior in which any port disconnect or
port disable causes the entire device structure to be removed, fixing a
reported regression.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1069c) changes the way OHCI root-hub status-change
interrupts are enabled. Currently a special HCD method,
hub_irq_enable(), is called when the hub driver is finished using a
root hub. This approach turns out to be subject to races, resulting
in unnecessary polling.
The patch does away with the method entirely. Instead, the driver
automatically enables the RHSC interrupt when no more status changes
are present. This scheme is safe with controllers using
level-triggered semantics for their interrupt flags.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1109b) makes USB-Persist more resilient to errors. With
the current code, if a normal resume fails, it's an unrecoverable
error. With the patch, if a normal resume fails (and if the device is
enabled for USB-Persist) then a reset-resume is tried.
This fixes the problem reported in Bugzilla #10977.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1024) takes care of a FIXME issue: Drivers that don't
have the necessary suspend, resume, reset_resume, pre_reset, or
post_reset methods will be unbound and their interface reprobed when
one of the unsupported events occurs.
This is made slightly more difficult by the fact that bind operations
won't work during a system sleep transition. So instead the code has
to defer the operation until the transition ends.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch renames the existing usb_reset_device in hub.c to
usb_reset_and_verify_device and renames the existing
usb_reset_composite_device to usb_reset_device. Also the new
usb_reset_and_verify_device does't need to be EXPORTED .
The idea of the patch is that external interface driver
should warn the other interfaces' driver of the same
device before and after reseting the usb device. One interface
driver shoud call _old_ usb_reset_composite_device instead of
_old_ usb_reset_device since it can't assume the device contains
only one interface. The _old_ usb_reset_composite_device
is safe for single interface device also. we rename the two
functions to make the change easily.
This patch is under guideline from Alan Stern.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
From the current implementation of usb_reset_composite_device
function, the iface parameter is no longer useful. This function
doesn't do something special for the iface usb_interface,compared
with other interfaces in the usb_device. So remove the parameter
and fix the related caller.
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We can't allow hubs on the 7th tier as they would allow
devices on the 8th tier.
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1083) combines hub_quiesce() and hub_stop() into a
single routine. There's no point keeping them separate since they are
usually called together.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1071) combines hub_activate() and hub_restart() into a
single routine. There's no point keeping them separate, since they
are always called together.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1082) makes a small optimization to the way the hub
driver carries out port debouncing immediately after a hub is
activated (i.e., initialized, reset, or resumed). If any port-change
statuses are observed, the code will delay for a minimal debounce
period -- thereby making a good start at debouncing all the ports at
once.
If this wasn't sufficient then khubd will debounce any port that still
requires attention. But in most cases it should suffice; it's rare
for a device to need more than a minimal debounce delay. (In the
cases of hub initialization or reset even that is most likely not
needed, since any devices plugged in at such times have probably been
attached for a while.)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1073) adds to khubd a way to recover from power-session
interruption caused by transient connect-change or enable-change
events. After the debouncing period, khubd attempts to do a
USB-Persist-style reset or reset-resume. If it works, the connection
will remain unscathed.
The upshot is that we will be more immune to noise caused by EMI. The
grace period is on the order of 100 ms, so this won't permit recovery
from the "accidentally knocked the USB cable out of its socket" type
of event, but it's a start.
As an added bonus, if a device was suspended when the system goes to
sleep then we no longer need to check for power-session interruptions
when the system wakes up. Khubd will naturally see the status change
while processing the device's parent hub and will do the right thing.
The remote_wakeup() routine is changed; now it expects the caller to
acquire the device lock rather than acquiring the lock itself.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1081) straightens out the logic of the hub_restart()
routine. Each port of the hub is scanned and the driver makes sure
that ports which are supposed to be disabled really _are_ disabled.
Any ports with a significant change in status are flagged in
hub->change_bits, so that khubd can focus on them without the need to
scan all the ports a second time -- which means the hub->activating
flag is no longer needed.
Also, it is now recognized explicitly that the only reason for
resuming a port which was not suspended is to carry out a reset-resume
operation, which happens only in a non-CONFIG_USB_SUSPEND setting.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts Linus's previous patch that is in mainline to make it
easier for the USB hub.c patches that follow this to apply cleanly. The
functionality will be added back in a followon patch in this series.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1080) makes a significant change to the way khubd
handles port connect-change and enable-change events. Both types of
event are now debounced, and the debouncing is carried out _before_ an
existing usb_device is unregistered, instead of afterward.
This means that drivers will have to deal with longer runs of errors
when a device is unplugged, but they are supposed to be prepared for
that in any case.
The advantage is that when an enable-change occurs (caused for example
by electromagnetic interference), the debouncing period will provide
time for the cause of the problem to die away. A simple port reset
(added in a forthcoming patch) will then allow us to recover from the
fault.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1070) creates a new subroutine to check whether a device
can be resumed. This code is needed even when CONFIG_USB_SUSPEND
isn't set, because devices do suspend themselves when the root hub
(and hence the entire bus) is suspended, and power sessions can get
lost during a system sleep even without individual port suspends.
The patch also fixes a loose end in USB-Persist reset-resume handling.
When a low- or full-speed device is attached to an EHCI's companion
controller, the port handoff during resume will cause the companion
port's connect-status-change feature to be set. If that flag isn't
cleared, the port-reset code will think it indicates that the device
has been unplugged and the reset-resume will fail.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts Alan's previous patch so that the recent Hub changes will
apply cleanly. The above mentioned patch was needed for 2.6.26 to work
properly.
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Lukas Hejtmanek <xhejtman@ics.muni.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This reverts commit e872154921.
Andrey Borzenkov reports that it resulted in a totally hung machine for
him when loading the OHCI driver. Extensive netconsole capture with
SysRq output shows that modprobe gets stuck in ohci_hub_status_data()
when probing and enabling the OHCI controller, see for example
http://lkml.org/lkml/2008/7/5/236
for an analysis.
The problem appears to be an interrupt flood triggered by the commit
that gets reverted, and Andrey confirmed that the revert makes things
work for him again.
Reported-and-tested-by: Andrey Borzenkov <arvidjaar@mail.ru>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Brownell <david-b@pacbell.net>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch (as1111) fixes a bug in the hub driver. When a hub
resumes, disconnections that occurred while the hub was suspended are
lost.
A completely different fix for this problem has already been accepted
for 2.6.27; however the problem still needs to be handled in 2.6.26.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Lukas Hejtmanek <xhejtman@ics.muni.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch tries to identify which devices are able to accept
reset-resume handling, by checking that there is at least one
interface driver bound and that all of the drivers have a reset_resume
method defined. If these conditions don't hold then during resume
processing, the device is logicall disconnected.
This is only a temporary fix. Later on we will explicitly unbind
drivers that can't handle reset-resumes.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: Pavel Machek <pavel@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1096) fixes an annoying problem: When a full-speed or
low-speed device is plugged into an EHCI controller, it fails to
enumerate at high speed and then is handed over to the companion
controller. But usbcore logs a misleading and unwanted error message
when the high-speed enumeration fails.
The patch adds a new HCD method, port_handed_over, which asks whether
a port has been handed over to a companion controller. If it has, the
error message is suppressed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
There is a potential deadlock when the usb_generic driver is unbound
from a device. The problem is that generic_disconnect() is called
with the device lock held, and it removes a bunch of device attributes
from sysfs. If a user task happens to be running an attribute method
at the time, the removal will block until the method returns. But at
least one of the attribute methods (the store routine for power/level)
needs to acquire the device lock!
This patch (as1093) eliminates the deadlock by moving the calls to
create and remove the sysfs attributes from the usb_generic driver
into usb_new_device() and usb_disconnect(), where they can be invoked
without holding the device lock.
Besides, the other sysfs attributes are created when the device is
registered and removed when the device is unregistered. So it seems
only fitting for the extra attributes to be created and removed at the
same time.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
For WUSB devices, usb_dev.devnum is a device index and not the real
device address (which is managed by wusbcore). Therefore, only set
devnum once (in choose_address()) and never change it.
Signed-off-by: David Vrabel <david.vrabel@csr.com>
Cc: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
We need to be able to call ep0_reinit() [renamed to usb_ep0_reinit()]
from the WUSB security code. The reason is that when we authenticate
the device, it's address changes (from having bit 7 set to having it
cleared). Thus, we need to signal the USB stack to reinitialize EP0,
so the status with the previous address kept at the HCD layer is
cleared and properly reinitialized.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A WUSB device gets his address during the connection phase; later on,
during the authenthication phase (driven from user space) we assign
the final address. So we need to skip in hub_port_init() the actual
setting of the address for WUSB devices.
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Modify choose_address() so it knows about our special scheme of
addressing WUSB devices (1:1 w/ port number).
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1069b) changes the way OHCI root-hub status-change
interrupts are enabled. Currently a special HCD method,
hub_irq_enable(), is called when the hub driver is finished using a
root hub. This approach turns out to be subject to races, resulting
in unnecessary polling.
The patch does away with the method entirely. Instead, the driver
automatically enables the RHSC interrupt when no more status changes
are present. This scheme is safe with controllers using
level-triggered semantics for their interrupt flags.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1077) logs an error message whenever the kernel is
unable to enumerate a new USB device.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1048) extends the descriptor checking after a device is
reset. Now the SerialNumber string descriptor is compared to its old
value, in addition to the device and configuration descriptors.
As a consequence, the kmalloc() call in usb_string() is now on the
error-handling pathway for usb-storage. Hence its allocation type is
changed to GFO_NOIO.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1047) removes the USB_PERSIST Kconfig option, enabling
it permanently. It also prevents the power/persist attribute from
being created for hub devices; there's no point in having it since
USB-PERSIST is always turned on for hubs.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1046) makes USB-PERSIST work more in accordance with
the documentation. Currently it takes effect only in cases where the
root hub has lost power or been reset, but it is supposed to operate
whenever a power session was dropped during a system sleep.
A new hub_restart() routine carries out the duties required during a
reset or a reset-resume. It checks to see whether occupied ports are
still enabled, and if they aren't then it clears the enable-change and
connect-change features (to prevent interference by khubd) and sets
the child device's reset_resume flag. It also checks ports that are
supposed to be unoccupied to verify that the firmware hasn't left the
port in an enabled state.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1045) reorganizes some code in the hub driver.
hub_port_status() is moved earlier in the file, and a new hub_stop()
routine is created to do the work currently in hub_preset() (i.e.,
disconnect all child devices and quiesce the hub).
There are no functional changes.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1044) causes EHCI port handover for non-high-speed
devices to occur during every root-hub resume, not just in cases where
the controller lost power or was reset. This is necessary because:
When some machines go into suspend, they remove power from
on-board USB devices while retaining suspend current for USB
controllers.
The user might well unplug a USB device while the system is
suspended and then plug it back in before resuming.
A corresponding change is made to the core resume routine; now
high-speed root hubs will always be resumed when the system wakes up,
even if they were suspended before the system went to sleep. If this
weren't done then EHCI port handover wouldn't work, since it is called
when the EHCI root hub is resumed.
Finally, a comment is added to the hub driver explaining the khubd has
to be freezable; if it weren't frozen then it could interfere with
port handover.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
None of these files use any of the functionality promised by
asm/semaphore.h. It's possible that they rely on it dragging in some
unrelated header file, but I can't build all these files, so we'll have
fix any build failures as they come up.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Over two years ago, the Linux USB developers stated that they believed
there was no way to create a USB kernel driver that was not under the
GPL. This patch moves the USB apis to enforce that decision.
There are no known closed source USB drivers in the wild, so this patch
should cause no problems.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch exports two statistics to userspace:
/sys/bus/usb/device/.../power/connected_duration
/sys/bus/usb/device/.../power/active_duration
connected_duration is the total time (in msec) that the device has
been connected. active_duration is the total time the device has not
been suspended. With these two statistics, tools like PowerTOP can
calculate the percentage time that a device is active, i.e. not
suspended or auto-suspended.
Users can also use the active_duration to check if a device is actually
autosuspended. Currently, they can set power/level to auto and
power/autosuspend to a positive timeout, but there's no way to know from
userspace if a device was actually autosuspended without looking at the
dmesg output. These statistics will be useful in creating an automated
userspace script to test autosuspend for USB devices.
Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1023) updates the code in usb_reset_composite_device():
Some local variable declarations are moved to inner loops.
The interface locks are not acquired. This isn't necessary
any more; its only reason was to prevent an interface from
being suspended or resumed during the reset. But now
interface power management is controlled by the USB device
lock, not by the interface lock.
The check for whether the interface is registered is removed.
There doesn't seem to be any reason for checking; a driver
for a non-registered interface deserves to be informed of
device resets just as much as any other.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Distros (like SuSE) want to know this information, to make it easier
to handle support issues. Might as well let everyone benefit from this.
This is also enabled whenever CONFIG_USB_DEBUG is enabled, to help with
debugging.
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch hands over the port to the companion when the
hub_port_connect_change fails.
Signed-off-by: Balaji Rao <balajirrao@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
this function will run in the context of the scsi error handler thread.
It must use GFP_NOIO instead of GFP_KERNEL to avoid a possible
deadlock.
Cc: stable <stable@kernel.org>
Signed-off-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1027) replaces a call to flush_scheduled_work() -- a
dangerous routine to invoke, especially while holding any sort of lock
-- with calls to cancel_work_sync() and cancel_delayed_work_sync().
This fixes Bugzilla #9532.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: David Brownell <david-b@pacbell.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Introduce freezer-friendly wrappers around wait_event_interruptible() and
wait_event_interruptible_timeout(), originally defined in <linux/wait.h>, to
be used in freezable kernel threads. Make some of the freezable kernel
threads use them.
This is necessary for the freezer to stop sending signals to kernel threads,
which is implemented in the next patch.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Fix USB docbook warnings.
Warning(linux-2.6.23-git8//include/linux/usb/gadget.h:487): No description found for parameter 'g'
Warning(linux-2.6.23-git8//include/linux/usb/gadget.h:506): No description found for parameter 'g'
Warning(linux-2.6.23-git8//drivers/usb/core/hub.c:1416): No description found for parameter 'usb_dev'
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch (as999) fixes a problem that sometimes shows up when host
controller driver modules are loaded in the wrong order. If ehci-hcd
happens to initialize an EHCI controller while the companion OHCI or
UHCI controller is in the middle of a port reset, the reset can fail
and the companion may get very confused. The patch adds an
rw-semaphore and uses it to keep EHCI initialization and port resets
mutually exclusive.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: David Brownell <david-b@pacbell.net>
Cc: David Miller <davem@davemloft.net>
Cc: Dely L Sy <dely.l.sy@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Alan Stern