How it's supposed to work:
--------------------------
USB 2.0 Link PM is a lower power state that some newer USB 2.0 devices
support. USB 3.0 devices certified by the USB-IF are required to
support it if they are plugged into a USB 2.0 only port, or a USB 2.0
cable is used. USB 2.0 Link PM requires both a USB device and a host
controller that supports USB 2.0 hardware-enabled LPM.
USB 2.0 Link PM is designed to be enabled once by software, and the host
hardware handles transitions to the L1 state automatically. The premise
of USB 2.0 Link PM is to be able to put the device into a lower power
link state when the bus is idle or the device NAKs USB IN transfers for
a specified amount of time.
...but hardware is broken:
--------------------------
It turns out many USB 3.0 devices claim to support USB 2.0 Link PM (by
setting the LPM bit in their USB 2.0 BOS descriptor), but they don't
actually implement it correctly. This manifests as the USB device
refusing to respond to transfers when it is plugged into a USB 2.0 only
port under the Haswell-ULT/Lynx Point LP xHCI host.
These devices pass the xHCI driver's simple test to enable USB 2.0 Link
PM, wait for the port to enter L1, and then bring it back into L0. They
only start to break when L1 entry is interleaved with transfers.
Some devices then fail to respond to the next control transfer (usually
a Set Configuration). This results in devices never enumerating.
Other mass storage devices (such as a later model Western Digital My
Passport USB 3.0 hard drive) respond fine to going into L1 between
control transfers. They ACK the entry, come out of L1 when the host
needs to send a control transfer, and respond properly to those control
transfers. However, when the first READ10 SCSI command is sent, the
device NAKs the data phase while it's reading from the spinning disk.
Eventually, the host requests to put the link into L1, and the device
ACKs that request. Then it never responds to the data phase of the
READ10 command. This results in not being able to read from the drive.
Some mass storage devices (like the Corsair Survivor USB 3.0 flash
drive) are well behaved. They ACK the entry into L1 during control
transfers, and when SCSI commands start coming in, they NAK the requests
to go into L1, because they need to be at full power.
Not all USB 3.0 devices advertise USB 2.0 link PM support. My Point
Grey USB 3.0 webcam advertises itself as a USB 2.1 device, but doesn't
have a USB 2.0 BOS descriptor, so we don't enable USB 2.0 Link PM. I
suspect that means the device isn't certified.
What do we do about it?
-----------------------
There's really no good way for the kernel to test these devices.
Therefore, the kernel needs to disable USB 2.0 Link PM by default, and
distros will have to enable it by writing 1 to the sysfs file
/sys/bus/usb/devices/../power/usb2_hardware_lpm. Rip out the xHCI Link
PM test, since it's not sufficient to detect these buggy devices, and
don't automatically enable LPM after the device is addressed.
This patch should be backported to kernels as old as 3.11, that
contain the commit a558ccdcc7 "usb: xhci:
add USB2 Link power management BESL support". Without this fix, some
USB 3.0 devices will not enumerate or work properly under USB 2.0 ports
on Haswell-ULT systems.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@vger.kernel.org
This patch straightens out some locking issues in the USB sysfs
interface:
Deauthorization will destroy existing configurations.
Attributes that read from udev->actconfig need to lock the
device to prevent races. Likewise for the rawdescriptor
values.
Attributes that access an interface's current alternate
setting should use ACCESS_ONCE() to obtain the cur_altsetting
pointer, to protect against concurrent altsetting changes.
The supports_autosuspend() attribute routine accesses values
from an interface's driver, so it should lock the interface
(rather than the usb_device) to protect against concurrent
unbinds. Once this is done, the routine can be simplified
considerably.
Scalar values that are stored directly in the usb_device structure are
always available. They do not require any locking. The same is true
of the cached interface string descriptor, because it is not
deallocated until the usb_host_interface structure is destroyed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of having to audit all sysfs attributes, to ensure we get them
right, use the default macros the driver core provides us (read-only,
read-write) to make the code simpler, and to prevent any mistakes from
ever happening.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Adds abitilty to tune L1 timeout (inactivity timer for usb2 link sleep)
and BESL (best effort service latency)via sysfs.
This also adds a new usb2_lpm_parameters structure with those variables to
struct usb_device.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
This patch (as1675) removes the CONFIG_USB_SUSPEND option, essentially
replacing it everywhere with CONFIG_PM_RUNTIME (except for one place
in hub.c, where it is replaced with CONFIG_PM because the code needs
to be used in both runtime and system PM). The net result is code
shrinkage and simplification.
There's very little point in keeping CONFIG_USB_SUSPEND because almost
everybody enables it. The few that don't will find that the usbcore
module has gotten somewhat bigger and they will have to take active
measures if they want to prevent hubs from being runtime suspended.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The USB 2.0 specification says that bMaxPower is the maximum power
consumption expressed in 2 mA units and the USB 3.0 specification says
that it is expressed in 8 mA units.
This patch adds a helper function usb_get_max_power() which computes the
value based on config & usb_device's speed value. The the device descriptor
dump computes the value on its own.
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since the attribute avoid_reset_quirk is work for all devices including
those devices that can't morph, convert USB_QUIRK_RESET_MORPHS to
USB_QUIRK_RESET.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In USB, the word "config" already has aseparate meaning. So it will
cause confusion if use "config" as variable's name for other purposes.
This patch is to convert the "config" to "val"
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB 3.0 devices can optionally support Latency Tolerance Messaging
(LTM). Add a new sysfs file in the device directory to show whether a
device is LTM capable. This file will be present for both USB 2.0 and
USB 3.0 devices.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Some composite USB devices provide multiple interfaces
with different functions, all using "vendor-specific"
for class/subclass/protocol. Another OS use interface
numbers to match the driver and interface. It seems
these devices are designed with that in mind - using
static interface numbers for the different functions.
This adds support for matching against the
bInterfaceNumber, allowing such devices to be supported
without having to resort to testing against interface
number whitelists and/or blacklists in the probe.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch (as1554) fixes a lockdep false-positive report. The
problem arises because lockdep is unable to deal with the
tree-structured locks created by the device core and sysfs.
This particular problem involves a sysfs attribute method that
unregisters itself, not from the device it was called for, but from a
descendant device. Lockdep doesn't understand the distinction and
reports a possible deadlock, even though the operation is safe.
This is the sort of thing that would normally be handled by using a
nested lock annotation; unfortunately it's not feasible to do that
here. There's no sensible way to tell sysfs when attribute removal
occurs in the context of a parent attribute method.
As a workaround, the patch adds a new flag to struct attribute
telling sysfs not to inform lockdep when it acquires a readlock on a
sysfs_dirent instance for the attribute. The readlock is still
acquired, but lockdep doesn't know about it and hence does not
complain about impossible deadlock scenarios.
Also added are macros for static initialization of attribute
structures with the ignore_lockdep flag set. The three offending
attributes in the USB subsystem are converted to use the new macros.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Tejun Heo <tj@kernel.org>
CC: Eric W. Biederman <ebiederm@xmission.com>
CC: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Userspace may want to make policy decisions based on whether or not a
given USB device is removable. Add a per-device member and support
for exposing it in sysfs. Information sources to populate it will be
added later.
Signed-off-by: Matthew Garrett <mjg@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch adds sysfs support to xHCI usb2 hardware LPM, so developer can
enable and disable usb2 hardware LPM manually for test purpose.
Signed-off-by: Andiry Xu <andiry.xu@amd.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The usb_create_sysfs_intf_files() function always returned zero even
if it failed to create sysfs fails. Since this is a desired behaviour
there is no need to return return code at all. This commit changes
function's return type (form int) to void.
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1428) converts USB over to the new runtime-PM core
autosuspend framework. One slightly awkward aspect of the conversion
is that USB devices will now have two suspend-delay attributes: the
old power/autosuspend file and the new power/autosuspend_delay_ms
file. One expresses the delay time in seconds and the other in
milliseconds, but otherwise they do the same thing. The old attribute
can be deprecated and then removed eventually.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1426) makes use of the new sysfs_merge_group() and
sysfs_unmerge_group() routines to simplify the handling of power
attributes for USB devices.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This allows bin_attr->read,write,mmap callbacks to check file specific data
(such as inode owner) as part of any privilege validation.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1367) deprecates USB's power/level sysfs attribute in
favor of the power/control attribute provided by the runtime PM core.
The two attributes do the same thing.
It would be nice to replace power/level with a symlink to
power/control, but at the moment sysfs doesn't offer any way to do so.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1366) replaces the private routines
usb_enable_autosuspend() and usb_disable_autosuspend() with calls to
the standard pm_runtime_allow() and pm_runtime_forbid() functions in
the runtime PM framework. They do the same thing.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1327) changes the way negative autosuspend delays
prevent device from autosuspending. The current code checks for
negative values explicitly in the autosuspend_check() routine. The
updated code keeps things from getting that far by using
usb_autoresume_device() to increment the usage counter when a negative
delay is set, and by using usb_autosuspend_device() to decrement the
usage counter when a non-negative delay is set.
This complicates the set_autosuspend() attribute method code slightly,
but it will reduce the overall power management overhead.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1326) adds usb_enable_autosuspend() and
usb_disable_autosuspend() routines for use by drivers. If a driver
knows that its device can handle suspends and resumes correctly, it
can enable autosuspend all by itself. This is equivalent to the user
writing "auto" to the device's power/level attribute.
The implementation differs slightly from what it used to be. Now
autosuspend is disabled simply by doing usb_autoresume_device() (to
increment the usage counter) and enabled by doing
usb_autosuspend_device() (to decrement the usage counter).
The set_level() attribute method is updated to use the new routines,
and the USB Power-Management documentation is updated.
The patch adds a usb_enable_autosuspend() call to the hub driver's
probe routine, allowing the special-case code for hubs in quirks.c to
be removed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1325) changes the locking for the persist_enabled flag
in struct usb_device. Now it is protected by the device lock, along
with all its neighboring bit flags, instead of the PM lock (which is
about to vanish anyway).
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1323) changes the locking requirements for
usb_autosuspend_device(), usb_autoresume_device(), and
usb_try_autosuspend_device(). This isn't a very important change;
mainly it's meant to make the locking more uniform.
The most tricky part of the patch involves changes to usbdev_open().
To avoid an ABBA locking problem, it was necessary to reduce the
region protected by usbfs_mutex. Since that mutex now protects only
against simultaneous open and remove, this posed no difficulty -- its
scope was larger than necessary.
And it turns out that usbfs_mutex is no longer needed in
usbdev_release() at all. The list of usbfs "ps" structures is now
protected by the device lock instead of by usbfs_mutex.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
It's really the wireless speed, so rename the thing to make
more sense. Based on a recommendation from David Vrabel
Cc: David Vrabel <david.vrabel@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Some devices which use mode switching revert to their
primary mode as they are reset. They must not be reset for
error handling. As user spaces makes the switch it also
has to tell the kernel that a device is quirky.
Signed-off-by: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
These controllers say "unknown" for their speed in sysfs, which
obviously isn't correct.
Reported-by: Kurt Garloff <garloff@novell.com>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: stable <stable@kernel.org>
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 (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>
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>
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>
Fix 3 sparse warning in drivers/usb/core/sysfs.c.
warning: symbol '__mptr' shadows an earlier one
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Apparently the Configuration and Interface strings aren't used as
often as the Vendor, Product, and Serial strings. In at least one
device (a Saitek Cyborg Gold 3D joystick), attempts to read the
Configuration string cause the device to stop responding to Control
requests.
This patch (as1226) adds a quirks flag, telling the kernel not to
read a device's Configuration or Interface strings, together with a
new quirk for the offending joystick.
Reported-by: Melchior FRANZ <melchior.franz@gmail.com>
Tested-by: Melchior FRANZ <melchior.franz@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org> [2.6.28 and 2.6.29, nothing earlier]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1185) makes usbcore take advantage of the bus
notifications sent out by the driver core. Now we can create all our
device and interface attribute files before the device or interface
uevent is broadcast.
A side effect is that we no longer create the endpoint "pseudo"
devices at the same time as a device or interface is registered -- it
seems like a bad idea to try registering an endpoint before the
registration of its parent is complete. So the routines for creating
and removing endpoint devices have been split out and renamed, and
they are called explicitly when needed. A new bitflag is used for
keeping track of whether or not the interface's endpoint devices have
been created, since (just as with the interface attributes) they vary
with the altsetting and hence can be changed at random times.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1177) modifies the USB core suspend and resume
routines. The resume functions now will take a pm_message_t argument,
so they will know what sort of resume is occurring. The new argument
is also passed to the port suspend/resume and bus suspend/resume
routines (although they don't use it for anything but debugging).
In addition, special pm_message_t values are used for user-initiated,
device-initiated (i.e., remote wakeup), and automatic suspend/resume.
By testing these values, drivers can tell whether or not a particular
suspend was an autosuspend. Unfortunately, they can't do the same for
resumes -- not until the pm_message_t argument is also passed to the
drivers' resume methods. That will require a bigger change.
IMO, the whole Power Management framework should have been set up this
way in the first place.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1156) straightens out some code in usbcore. The
usb_create_intf_ep_files() and usb_remove_intf_ep_files() routines
don't need to be separate inlines; they should be moved bodily into
the places where they get used.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1155) fixes a bug in usbcore. When interfaces are
deleted, either because the device was disconnected or because of a
configuration change, the extra attribute files and child endpoint
devices may get left behind. This is because the core removes them
before calling device_del(). But during device_del(), after the
driver is unbound the core will reinstall altsetting 0 and recreate
those extra attributes and children.
The patch prevents this by adding a flag to record when the interface
is in the midst of being unregistered. When the flag is set, the
attribute files and child devices will not be created.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: stable <stable@kernel.org> [2.6.27, 2.6.26, 2.6.25]
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Create a new sysfs file per interface named supports_autosuspend. This
file returns true if an interface driver's .supports_autosuspend flag is
set. It also returns true if the interface is unclaimed (since the USB
core will autosuspend a device if an interface is not claimed).
This new sysfs file will be useful for user space scripts to test whether
a USB device correctly auto-suspends.
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: Oliver Neukum <oliver@neukum.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1094) changes the output of the "descriptors" binary
attribute. Now it will contain the device descriptor followed by all
the configuration descriptors, not just the descriptor for the current
config.
Userspace libraries want to have access to the kernel's cached
descriptor information, so they can learn about device characteristics
without having to wake up suspended devices. So far the only user of
this attribute is the new libusb-1.0 library; thus changing its
contents shouldn't cause any problems.
This should be considered for 2.6.26, if for no other reason than to
minimize the range of releases in which the attribute contains only the
current config descriptor.
Also, it doesn't hurt that the patch removes the device locking --
which was formerly needed in order to know for certain which config was
indeed current.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as1087d) fixes a long-standing problem in usbcore: Device,
interface, and endpoint attributes aren't added until _after_ the
creation uevent has already been broadcast.
Unfortunately there are a few attributes which cannot be created that
early. The "descriptors" attribute is binary and so must be created
separately. The power-management attributes can't be created until
the dev/power/ group exists. And the interface string can vary from
one altsetting to another, so it has to be created dynamically.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Kay Sievers <kay.sievers@vrfy.org>
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 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 (as1009) solves the problem of multiple registrations for
USB sysfs files in a more satisfying way than the existing code. It
simply adds a flag to keep track of whether or not the files have been
created; that way the files can be created or removed as needed.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
powertop currently tracks interrupts generated by uhci, ehci, and ohci,
but it has no way of telling which USB device to blame USB bus activity on.
This patch exports the number of URBs that are submitted for a given device.
Cat the file 'urbnum' in /sys/bus/usb/devices/.../
Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Makes it possible to control the authorization of USB devices through
sysfs's /sys/usb/devices/*/authorize.
Update: per Adrian Bunk's suggestion, make dev_attr_authorized_default static
Signed-off-by: Inaky Perez-Gonzalez <inaky@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch (as934) adds a new readonly binary sysfs attribute file
called "descriptors" for each USB device. The attribute contains the
device descriptor followed by the raw descriptor entry (config plug
subsidiary descriptors) for the current configuration.
Having this information available in fixed-format binary makes life a
lot easier for user programs by avoiding the need to open, read, and
parse multiple sysfs text files.
The information in this attribute file is much like that in usbfs's
device file, but there are some significant differences:
The 2-byte fields in the device descriptor are left in
little-endian byte order, as they appear on the bus and
in the kernel.
Only one raw descriptor set is presented, that of the
current configuration.
Opening this file will not cause a suspended device to be
autoresumed.
The last item in particular should be a big selling point for libusb,
which currently forces all USB devices to be resumed as it scans the
device tree.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Dave Mielke <dave@mielke.cc>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Rahul Bedarkar