linux-stable.git/drivers/usb/core/generic.c, branch linux-5.4.y

usbfs: Add ioctls for runtime power management

2019-08-09T05:55:45+00:00

It has been requested that usbfs should implement runtime power
management, instead of forcing the device to remain at full power as
long as the device file is open. This patch introduces that new
feature.

It does so by adding three new usbfs ioctls:

USBDEVFS_FORBID_SUSPEND: Prevents the device from going into
runtime suspend (and causes a resume if the device is already
suspended).

USBDEVFS_ALLOW_SUSPEND: Allows the device to go into runtime
suspend. Some time may elapse before the device actually is
suspended, depending on things like the autosuspend delay.

USBDEVFS_WAIT_FOR_RESUME: Blocks until the call is interrupted
by a signal or at least one runtime resume has occurred since
the most recent ALLOW_SUSPEND ioctl call (which may mean
immediately, even if the device is currently suspended). In
the latter case, the device is prevented from suspending again
just as if FORBID_SUSPEND was called before the ioctl returns.

For backward compatibility, when the device file is first opened
runtime suspends are forbidden. The userspace program can then allow
suspends whenever it wants, and either resume the device directly (by
forbidding suspends again) or wait for a resume from some other source
(such as a remote wakeup). URBs submitted to a suspended device will
fail or will complete with an appropriate error code.

This combination of ioctls is sufficient for user programs to have
nearly the same degree of control over a device's runtime power
behavior as kernel drivers do.

Still lacking is documentation for the new ioctls. I intend to add it
later, after the existing documentation for the usbfs userspace API is
straightened out into a reasonable form.

Suggested-by: Mayuresh Kulkarni
Signed-off-by: Alan Stern

Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.1908071013220.1514-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman

USB: Fix configuration selection issues introduced in v4.20.0

2019-02-08T09:22:39+00:00

Commit f13912d3f014a introduced changes to the usb_choose_configuration function
to better support USB Audio UAC3-compatible devices. However, there are a few
problems with this patch. First of all, it adds new "if" clauses in the middle
of an existing "if"/"else if" tree, which obviously breaks pre-existing logic.
Secondly, since it continues iterating over configurations in one of the branches,
other code in the loop can choose an unintended configuration. Finally,
if an audio device's first configuration is UAC3-compatible, and there
are multiple UAC3 configurations, the second one would be chosen, due to
the first configuration never being checked for UAC3-compatibility.

Commit ff2a8c532c14 tries to fix the second issue, but it goes about it in a
somewhat unnecessarily convoluted way, in my opinion, and does nothing
to fix the first or the last one.

This patch tries to rectify problems described by essentially rewriting
code introduced in f13912d3f014a. Notice the code was moved to *before*
the "if"/"else if" tree.

Signed-off-by: Nikolay Yakimov 
Signed-off-by: Greg Kroah-Hartman

usbcore: Select only first configuration for non-UAC3 compliant devices

2019-01-07T16:23:30+00:00

In most of the UAC1 and UAC2 audio devices, the first
configuration is most often the best configuration.
However, with recent patch to support UAC3 configuration,
second configuration was unintentionally chosen for
some of the UAC1/2 devices that had more than one
configuration. This was because of the existing check
after the audio config check which selected any config
which had a non-vendor class. This patch fixes this issue.

Fixes: f13912d3f014 ("usbcore: Select UAC3 configuration for audio if present")
Reported-by: Con Kolivas 
Signed-off-by: Saranya Gopal 
Tested-by: Con Kolivas 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

usbcore: Select UAC3 configuration for audio if present

2018-09-20T11:12:05+00:00

USB audio class 3.0 specification introduced many significant
changes like
 - new power domains, support for LPM/L1
 - new cluster descriptor
 - new high capability and class-specific string descriptors
 - BADD profiles
 - ... and many other things (check spec from link below:
http://www.usb.org/developers/docs/devclass_docs/USB_Audio_v3.0.zip)

Now that UAC3 is supported in linux, choose UAC3
configuration for audio if the device supports it.
Selecting this configuration will enable the system to
save power by leveraging the new power domains and LPM L1
capability and also support new codec types and data formats
for consumer audio applications.

Signed-off-by: Saranya Gopal 
Reviewed-by: Felipe Balbi 
Signed-off-by: Greg Kroah-Hartman

USB:fix USB3 devices behind USB3 hubs not resuming at hibernate thaw

2018-03-23T13:11:54+00:00

USB3 hubs don't support global suspend.

USB3 specification 10.10, Enhanced SuperSpeed hubs only support selective
suspend and resume, they do not support global suspend/resume where the
hub downstream facing ports states are not affected.

When system enters hibernation it first enters freeze process where only
the root hub enters suspend, usb_port_suspend() is not called for other
devices, and suspend status flags are not set for them. Other devices are
expected to suspend globally. Some external USB3 hubs will suspend the
downstream facing port at global suspend. These devices won't be resumed
at thaw as the suspend status flag is not set.

A USB3 removable hard disk connected through a USB3 hub that won't resume
at thaw will fail to synchronize SCSI cache, return “cmd cmplt err -71”
error, and needs a 60 seconds timeout which causing system hang for 60s
before the USB host reset the port for the USB3 removable hard disk to
recover.

Fix this by always calling usb_port_suspend() during freeze for USB3
devices.

Signed-off-by: Zhengjun Xing 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

USB: core: move existing SPDX tags to top of the file

2017-11-03T09:12:26+00:00

To match the rest of the kernel, the SPDX tags for the drivers/usb/core/
files are moved to the first line of the file.  This makes it more
obvious the tag is present as well as making it match the other 12k
files in the tree with this location.

It also uses // to match the "expected style" as well.

Signed-off-by: Greg Kroah-Hartman

USB: core: add missing license information to some files

2016-10-29T16:51:56+00:00

Some of the USB core files were missing explicit license information.
As all files in the kernel tree are implicitly licensed under the
GPLv2-only, be explicit in case someone get confused looking at
individual files by using the SPDX nomenclature.

Signed-off-by: Greg Kroah-Hartman

staging: usbip: convert usbip-host driver to usb_device_driver

2014-02-07T18:54:30+00:00

This driver was previously an interface driver. Since USB/IP
exports a whole device, not just an interface, it would make
sense to be a device driver.

This patch also modifies the way userspace sees and uses a
shared device:

* the usbip_status file is no longer created for interface 0, but for
the whole device (such as
/sys/devices/pci0000:00/0000:00:01.2/usb1/1-1/usbip_status).
* per interface information, such as interface class or protocol, is
no longer sent/received; only device specific information is
transmitted.
* since the driver was moved one level below in the USB architecture,
there is no need to bind/unbind each interface, just the device as a
whole.

Signed-off-by: Valentina Manea 
Signed-off-by: Greg Kroah-Hartman

USB: avoid error messages when a device is disconnected

2013-03-28T18:05:52+00:00

This patch (as1673) reduces the amount of log spew from the hub driver
by removing a bunch of error messages in the case where the device in
question is already known to have been disconnected.  Since the
disconnect event itself appears in the log, there's no need for other
error messages.

Signed-off-by: Alan Stern 
Tested-by: Jenya Y 
Signed-off-by: Greg Kroah-Hartman

usb/core: consider link speed while looking at bMaxPower

2013-01-12T00:16:01+00:00

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 
Cc: Greg Kroah-Hartman 
Acked-by: Alan Stern 
Signed-off-by: Sebastian Andrzej Siewior 
Signed-off-by: Greg Kroah-Hartman