When a USB driver is bound to an interface (either through probing or
by claiming it) or is unbound from an interface, the USB core always
disables Link Power Management during the transition and then
re-enables it afterward. The reason is because the driver might want
to prevent hub-initiated link power transitions, in which case the HCD
would have to recalculate the various LPM parameters. This
recalculation takes place when LPM is re-enabled and the new
parameters are sent to the device and its parent hub.
However, if the driver does not want to prevent hub-initiated link
power transitions then none of this work is necessary. The parameters
don't need to be recalculated, and LPM doesn't need to be disabled and
re-enabled.
It turns out that disabling and enabling LPM can be time-consuming,
enough so that it interferes with user programs that want to claim and
release interfaces rapidly via usbfs. Since the usbfs kernel driver
doesn't set the disable_hub_initiated_lpm flag, we can speed things up
and get the user programs to work by leaving LPM alone whenever the
flag isn't set.
And while we're improving the way disable_hub_initiated_lpm gets used,
let's also fix its kerneldoc.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Matthew Giassa <matthew@giassa.net>
CC: Mathias Nyman <mathias.nyman@intel.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The XHCI controller presents two USB buses to the system - one for USB2
and one for USB3. The hub init code (hub_port_init) is reentrant but
only locks one bus per thread, leading to a race condition failure when
two threads attempt to simultaneously initialise a USB2 and USB3 device:
[ 8.034843] xhci_hcd 0000:00:14.0: Timeout while waiting for setup device command
[ 13.183701] usb 3-3: device descriptor read/all, error -110
On a test system this failure occurred on 6% of all boots.
The call traces at the point of failure are:
Call Trace:
[<ffffffff81b9bab7>] schedule+0x37/0x90
[<ffffffff817da7cd>] usb_kill_urb+0x8d/0xd0
[<ffffffff8111e5e0>] ? wake_up_atomic_t+0x30/0x30
[<ffffffff817dafbe>] usb_start_wait_urb+0xbe/0x150
[<ffffffff817db10c>] usb_control_msg+0xbc/0xf0
[<ffffffff817d07de>] hub_port_init+0x51e/0xb70
[<ffffffff817d4697>] hub_event+0x817/0x1570
[<ffffffff810f3e6f>] process_one_work+0x1ff/0x620
[<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620
[<ffffffff810f4684>] worker_thread+0x64/0x4b0
[<ffffffff810f4620>] ? rescuer_thread+0x390/0x390
[<ffffffff810fa7f5>] kthread+0x105/0x120
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
[<ffffffff81ba183f>] ret_from_fork+0x3f/0x70
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
Call Trace:
[<ffffffff817fd36d>] xhci_setup_device+0x53d/0xa40
[<ffffffff817fd87e>] xhci_address_device+0xe/0x10
[<ffffffff817d047f>] hub_port_init+0x1bf/0xb70
[<ffffffff811247ed>] ? trace_hardirqs_on+0xd/0x10
[<ffffffff817d4697>] hub_event+0x817/0x1570
[<ffffffff810f3e6f>] process_one_work+0x1ff/0x620
[<ffffffff810f3dcf>] ? process_one_work+0x15f/0x620
[<ffffffff810f4684>] worker_thread+0x64/0x4b0
[<ffffffff810f4620>] ? rescuer_thread+0x390/0x390
[<ffffffff810fa7f5>] kthread+0x105/0x120
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
[<ffffffff81ba183f>] ret_from_fork+0x3f/0x70
[<ffffffff810fa6f0>] ? kthread_create_on_node+0x200/0x200
Which results from the two call chains:
hub_port_init
usb_get_device_descriptor
usb_get_descriptor
usb_control_msg
usb_internal_control_msg
usb_start_wait_urb
usb_submit_urb / wait_for_completion_timeout / usb_kill_urb
hub_port_init
hub_set_address
xhci_address_device
xhci_setup_device
Mathias Nyman explains the current behaviour violates the XHCI spec:
hub_port_reset() will end up moving the corresponding xhci device slot
to default state.
As hub_port_reset() is called several times in hub_port_init() it
sounds reasonable that we could end up with two threads having their
xhci device slots in default state at the same time, which according to
xhci 4.5.3 specs still is a big no no:
"Note: Software shall not transition more than one Device Slot to the
Default State at a time"
So both threads fail at their next task after this.
One fails to read the descriptor, and the other fails addressing the
device.
Fix this in hub_port_init by locking the USB controller (instead of an
individual bus) to prevent simultaneous initialisation of both buses.
Fixes: 638139eb95 ("usb: hub: allow to process more usb hub events in parallel")
Link: https://lkml.org/lkml/2016/2/8/312
Link: https://lkml.org/lkml/2016/2/4/748
Signed-off-by: Chris Bainbridge <chris.bainbridge@gmail.com>
Cc: stable <stable@vger.kernel.org>
Acked-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
SS+ also expresses intervals in units of 125ms. Testing must
be for SS or faster, not SS exactly.
Signed-off-by: Oliver neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
LTM is also defined for SS+. The correct test is to check for anything
slower than SS not exactly SS.
Signed-off-by: Oliver Neukum <ONeukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB 3.1 devices that support precision time measurement have an
additional PTM cabaility descriptor as part of the full BOS descriptor
Look for this descriptor while parsing the BOS descriptor, and store it in
struct usb_hub_bos if it exists.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB 3.1 devices can return a new SuperSpeedPlus isoc endpoint companion
descriptor for a isochronous endpoint that requires more than 48K bytes
per Service Interval.
The new descriptor immediately follows the old USB 3.0 SuperSpeed Endpoint
Companion and will provide a new BytesPerInterval value.
It is parsed and stored in struct usb_host_endpoint with the other endpoint
related descriptors, and should be used by USB3.1 capable hosts to reserve
bus time in the schedule.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
232275a USB: fix substandard locking for the sysfs files
introduced needed locking into sysfs operations on USB devices
It, however, uses uninterruptible sleep and if the error
handling is on extreme cases of sleep lengths of 10s of seconds
are possible. Unless we are removing the device we should use
interruptible sleep.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB bus numbering is based on directly dealing with bitmaps and
defines a separate list of busses.
This can be simplified and unified by using existing idr functionality.
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 8306095fd2 ("USB: Disable USB 3.0 LPM in critical sections.")
adds usb3_lpm_enabled member to struct usb_device. There is no reference
to this member now. Hence, it could be removed.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 655fe4effe ("usbcore: add sysfs support to xHCI usb3
hardware LPM") introduced usb3_hardware_lpm sysfs node. This
doesn't show the correct status of USB3 U1 and U2 LPM status.
This patch fixes this by replacing usb3_hardware_lpm with two
nodes, usb3_hardware_lpm_u1 (for U1) and usb3_hardware_lpm_u2
(for U2), and recording the U1/U2 LPM status in right places.
This patch should be back-ported to kernels as old as 4.3,
that contains Commit 655fe4effe ("usbcore: add sysfs support
to xHCI usb3 hardware LPM").
Cc: stable@vger.kernel.org
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If a device supports usb 3.1 SupeerSpeedPlus Gen2 speeds it povides
a SuperSpeedPlus device capability descriptor as a part of its
BOS descriptor. If we find one while parsing the BOS then save it
togeter with the other device capabilities found in the BOS
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Every USB Host controller should use this new
macro to define for how long resume signalling
should be driven on the bus.
Currently, almost every single USB controller
is using a 20ms timeout for resume signalling.
That's problematic for two reasons:
a) sometimes that 20ms timer expires a little
before 20ms, which makes us fail certification
b) some (many) devices actually need more than
20ms resume signalling.
Sure, in case of (b) we can state that the device
is against the USB spec, but the fact is that
we have no control over which device the certification
lab will use. We also have no control over which host
they will use. Most likely they'll be using a Windows
PC which, again, we have no control over how that
USB stack is written and how long resume signalling
they are using.
At the end of the day, we must make sure Linux passes
electrical compliance when working as Host or as Device
and currently we don't pass compliance as host because
we're driving resume signallig for exactly 20ms and
that confuses certification test setup resulting in
Certification failure.
Cc: <stable@vger.kernel.org> # v3.10+
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
The USB stack provides a mechanism for drivers to request an
asynchronous device reset (usb_queue_reset_device()). The mechanism
uses a work item (reset_ws) embedded in the usb_interface structure
used by the driver, and the reset is carried out by a work queue
routine.
The asynchronous reset can race with driver unbinding. When this
happens, we try to cancel the queued reset before unbinding the
driver, on the theory that the driver won't care about any resets once
it is unbound.
However, thanks to the fact that lockdep now tracks work queue
accesses, this can provoke a lockdep warning in situations where the
device reset causes another interface's driver to be unbound; see
http://marc.info/?l=linux-usb&m=141893165203776&w=2
for an example. The reason is that the work routine for reset_ws in
one interface calls cancel_queued_work() for the reset_ws in another
interface. Lockdep thinks this might lead to a work routine trying to
cancel itself. The simplest solution is not to cancel queued resets
when unbinding drivers.
This means we now need to acquire a reference to the usb_interface
when queuing a reset_ws work item and to drop the reference when the
work routine finishes. We also need to make sure that the
usb_interface structure doesn't outlive its parent usb_device; this
means acquiring and dropping a reference when the interface is created
and destroyed.
In addition, cancelling a queued reset can fail (if the device is in
the middle of an earlier reset), and this can cause usb_reset_device()
to try to rebind an interface that has been deallocated (see
http://marc.info/?l=linux-usb&m=142175717016628&w=2 for details).
Acquiring the extra references prevents this failure.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Reported-by: Russell King - ARM Linux <linux@arm.linux.org.uk>
Reported-by: Olivier Sobrie <olivier@sobrie.be>
Tested-by: Olivier Sobrie <olivier@sobrie.be>
Cc: stable <stable@vger.kernel.org> # 3.19
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After commit b2b49ccbdd (PM: Kconfig: Set PM_RUNTIME if PM_SLEEP is
selected) PM_RUNTIME is always set if PM is set, so quite a few
depend on CONFIG_PM (or even dropped in some cases).
Replace CONFIG_PM_RUNTIME with CONFIG_PM in the USB core code
and documentation.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With this patch, USB activity can be signaled by blinking a LED. There
are two triggers, one for activity on USB host and one for USB gadget.
Both triggers should work with all host/device controllers. Tested only
with musb.
Performace: I measured performance overheads on ARM Cortex-A8 (TI
AM335x) running on 600 MHz.
Duration of usb_led_activity():
- with no LED attached to the trigger: 2 ± 1 µs
- with one GPIO LED attached to the trigger: 2 ± 1 µs or 8 ± 2 µs (two peaks in histogram)
Duration of functions calling usb_led_activity() (with this patch
applied and no LED attached to the trigger):
- __usb_hcd_giveback_urb(): 10 - 25 µs
- usb_gadget_giveback_request(): 2 - 6 µs
Signed-off-by: Michal Sojka <sojka@merica.cz>
Acked-by: Felipe Balbi <balbi@ti.com>
Tested-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch creates a separate instance of the usb_address0 mutex for each USB
bus, and attaches it to the usb_bus device struct. This allows devices on
separate buses to be enumerated in parallel; saving time.
In the current code, there is a single, global instance of the usb_address0
mutex which is used for all devices on all buses. This isn't completely
necessary, as this mutex is only needed to prevent address0 collisions for
devices on the *same* bus (usb 2.0 spec, sec 4.6.1). This superfluous coverage
can cause additional delay in system resume on systems with multiple hosts
(up to several seconds depending on what devices are attached).
Signed-off-by: Todd Brandt <todd.e.brandt@linux.intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull USB patches from Greg KH:
"Here's the big USB pull request for 3.15-rc1.
The normal set of patches, lots of controller driver updates, and a
smattering of individual USB driver updates as well.
All have been in linux-next for a while"
* tag 'usb-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (249 commits)
xhci: Transition maintainership to Mathias Nyman.
USB: disable reset-resume when USB_QUIRK_RESET is set
USB: unbind all interfaces before rebinding any
usb: phy: Add ulpi IDs for SMSC USB3320 and TI TUSB1210
usb: gadget: tcm_usb_gadget: stop format strings
usb: gadget: f_fs: add missing spinlock and mutex unlock
usb: gadget: composite: switch over to ERR_CAST()
usb: gadget: inode: switch over to memdup_user()
usb: gadget: f_subset: switch over to PTR_RET
usb: gadget: lpc32xx_udc: fix wrong clk_put() sequence
USB: keyspan: remove dead debugging code
USB: serial: add missing newlines to dev_<level> messages.
USB: serial: add missing braces
USB: serial: continue to write on errors
USB: serial: continue to read on errors
USB: serial: make bulk_out_size a lower limit
USB: cypress_m8: fix potential scheduling while atomic
devicetree: bindings: document lsi,zevio-usb
usb: chipidea: add support for USB OTG controller on LSI Zevio SoCs
usb: chipidea: imx: Use dev_name() for ci_hdrc name to distinguish USBs
...
Since it is needed outside usbcore and exposed in include/linux/usb.h,
it conflicts with enum dev_state in rt2x00 wireless driver.
Mark it as usb specific to avoid conflicts in the future.
Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A device should not be able to be used concurrently both by
the server and the client. Claiming the port used by the
shared device ensures no interface drivers bind to it and
that it is not usable from the server.
Signed-off-by: Valentina Manea <valentina.manea.m@gmail.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
