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Commit 85d07c556216 ("USB: core: Unite old scheme and new scheme
descriptor reads") altered the way USB devices are enumerated
following detection, and in the process it messed up the
initialization of SuperSpeed (or faster) devices:
[ 31.650759] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 2 using xhci_hcd
[ 31.663107] usb 2-1: device descriptor read/8, error -71
[ 31.952697] usb 2-1: new SuperSpeed Plus Gen 2x1 USB device number 3 using xhci_hcd
[ 31.965122] usb 2-1: device descriptor read/8, error -71
[ 32.080991] usb usb2-port1: attempt power cycle
...
The problem was caused by the commit forgetting that in SuperSpeed or
faster devices, the device descriptor uses a logarithmic encoding of
the bMaxPacketSize0 value. (For some reason I thought the 255 case in
the switch statement was meant for these devices, but it isn't -- it
was meant for Wireless USB and is no longer needed.)
We can fix the oversight by testing for buf->bMaxPacketSize0 = 9
(meaning 512, the actual maxpacket size for ep0 on all SuperSpeed
devices) and straightening out the logic that checks and adjusts our
initial guesses of the maxpacket value.
Reported-and-tested-by: Thinh Nguyen <Thinh.Nguyen@synopsys.com>
Closes: https://lore.kernel.org/linux-usb/20230810002257.nadxmfmrobkaxgnz@synopsys.com/
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Fixes: 85d07c556216 ("USB: core: Unite old scheme and new scheme descriptor reads")
Link: https://lore.kernel.org/r/8809e6c5-59d5-4d2d-ac8f-6d106658ad73@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Wireless USB has long been defunct, and kernel support for it was
removed in 2020 by commit caa6772db4c1 ("Staging: remove wusbcore and
UWB from the kernel tree.").
Nevertheless, some vestiges of the old implementation still clutter up
the USB subsystem and one or two other places. Let's get rid of them
once and for all.
The only parts still left are the user-facing APIs in
include/uapi/linux/usb/ch9.h. (There are also a couple of misleading
instances, such as the Sierra Wireless USB modem, which is a USB modem
made by Sierra Wireless.)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/b4f2710f-a2de-4fb0-b50f-76776f3a961b@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Syzbot reported an out-of-bounds read in sysfs.c:read_descriptors():
BUG: KASAN: slab-out-of-bounds in read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
Read of size 8 at addr ffff88801e78b8c8 by task udevd/5011
CPU: 0 PID: 5011 Comm: udevd Not tainted 6.4.0-rc6-syzkaller-00195-g40f71e7cd3c6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106
print_address_description.constprop.0+0x2c/0x3c0 mm/kasan/report.c:351
print_report mm/kasan/report.c:462 [inline]
kasan_report+0x11c/0x130 mm/kasan/report.c:572
read_descriptors+0x263/0x280 drivers/usb/core/sysfs.c:883
...
Allocated by task 758:
...
__do_kmalloc_node mm/slab_common.c:966 [inline]
__kmalloc+0x5e/0x190 mm/slab_common.c:979
kmalloc include/linux/slab.h:563 [inline]
kzalloc include/linux/slab.h:680 [inline]
usb_get_configuration+0x1f7/0x5170 drivers/usb/core/config.c:887
usb_enumerate_device drivers/usb/core/hub.c:2407 [inline]
usb_new_device+0x12b0/0x19d0 drivers/usb/core/hub.c:2545
As analyzed by Khazhy Kumykov, the cause of this bug is a race between
read_descriptors() and hub_port_init(): The first routine uses a field
in udev->descriptor, not expecting it to change, while the second
overwrites it.
Prior to commit 45bf39f8df7f ("USB: core: Don't hold device lock while
reading the "descriptors" sysfs file") this race couldn't occur,
because the routines were mutually exclusive thanks to the device
locking. Removing that locking from read_descriptors() exposed it to
the race.
The best way to fix the bug is to keep hub_port_init() from changing
udev->descriptor once udev has been initialized and registered.
Drivers expect the descriptors stored in the kernel to be immutable;
we should not undermine this expectation. In fact, this change should
have been made long ago.
So now hub_port_init() will take an additional argument, specifying a
buffer in which to store the device descriptor it reads. (If udev has
not yet been initialized, the buffer pointer will be NULL and then
hub_port_init() will store the device descriptor in udev as before.)
This eliminates the data race responsible for the out-of-bounds read.
The changes to hub_port_init() appear more extensive than they really
are, because of indentation changes resulting from an attempt to avoid
writing to other parts of the usb_device structure after it has been
initialized. Similar changes should be made to the code that reads
the BOS descriptor, but that can be handled in a separate patch later
on. This patch is sufficient to fix the bug found by syzbot.
Reported-and-tested-by: syzbot+18996170f8096c6174d0@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/linux-usb/000000000000c0ffe505fe86c9ca@google.com/#r
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Khazhy Kumykov <khazhy@google.com>
Fixes: 45bf39f8df7f ("USB: core: Don't hold device lock while reading the "descriptors" sysfs file")
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/b958b47a-9a46-4c22-a9f9-e42e42c31251@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The usb_get_device_descriptor() routine reads the device descriptor
from the udev device and stores it directly in udev->descriptor. This
interface is error prone, because the USB subsystem expects in-memory
copies of a device's descriptors to be immutable once the device has
been initialized.
The interface is changed so that the device descriptor is left in a
kmalloc-ed buffer, not copied into the usb_device structure. A
pointer to the buffer is returned to the caller, who is then
responsible for kfree-ing it. The corresponding changes needed in the
various callers are fairly small.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/d0111bb6-56c1-4f90-adf2-6cfe152f6561@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In preparation for reworking the usb_get_device_descriptor() routine,
it is desirable to unite the two different code paths responsible for
initially determining endpoint 0's maximum packet size in a newly
discovered USB device. Making this determination presents a
chicken-and-egg sort of problem, in that the only way to learn the
maxpacket value is to get it from the device descriptor retrieved from
the device, but communicating with the device to retrieve a descriptor
requires us to know beforehand the ep0 maxpacket size.
In practice this problem is solved in two different ways, referred to
in hub.c as the "old scheme" and the "new scheme". The old scheme
(which is the approach recommended by the USB-2 spec) involves asking
the device to send just the first eight bytes of its device
descriptor. Such a transfer uses packets containing no more than
eight bytes each, and every USB device must have an ep0 maxpacket size
>= 8, so this should succeed. Since the bMaxPacketSize0 field of the
device descriptor lies within the first eight bytes, this is all we
need.
The new scheme is an imitation of the technique used in an early
Windows USB implementation, giving it the happy advantage of working
with a wide variety of devices (some of them at the time would not
work with the old scheme, although that's probably less true now). It
involves making an initial guess of the ep0 maxpacket size, asking the
device to send up to 64 bytes worth of its device descriptor (which is
only 18 bytes long), and then resetting the device to clear any error
condition that might have resulted from the guess being wrong. The
initial guess is determined by the connection speed; it should be
correct in all cases other than full speed, for which the allowed
values are 8, 16, 32, and 64 (in this case the initial guess is 64).
The reason for this patch is that the old- and new-scheme parts of
hub_port_init() use different code paths, one involving
usb_get_device_descriptor() and one not, for their initial reads of
the device descriptor. Since these reads have essentially the same
purpose and are made under essentially the same circumstances, this is
illogical. It makes more sense to have both of them use a common
subroutine.
This subroutine does basically what the new scheme's code did, because
that approach is more general than the one used by the old scheme. It
only needs to know how many bytes to transfer and whether or not it is
being called for the first iteration of a retry loop (in case of
certain time-out errors). There are two main differences from the
former code:
We initialize the bDescriptorType field of the transfer buffer
to 0 before performing the transfer, to avoid possibly
accessing an uninitialized value afterward.
We read the device descriptor into a temporary buffer rather
than storing it directly into udev->descriptor, which the old
scheme implementation used to do.
Since the whole point of this first read of the device descriptor is
to determine the bMaxPacketSize0 value, that is what the new routine
returns (or an error code). The value is stored in a local variable
rather than in udev->descriptor. As a side effect, this necessitates
moving a section of code that checks the bcdUSB field for SuperSpeed
devices until after the full device descriptor has been retrieved.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Cc: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/495cb5d4-f956-4f4a-a875-1e67e9489510@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In Realtek SoC, the parameter of usb phy is designed to can dynamic
tuning base on port status. Therefore, add a notify callback of phy
driver when usb port status change.
The Realtek phy driver is designed to dynamically adjust disconnection
level and calibrate phy parameters. When the device connected bit changes
and when the disconnected bit changes, do port status change notification:
Check if portstatus is USB_PORT_STAT_CONNECTION and portchange is
USB_PORT_STAT_C_CONNECTION.
1. The device is connected, the driver lowers the disconnection level and
calibrates the phy parameters.
2. The device disconnects, the driver increases the disconnect level and
calibrates the phy parameters.
When controller to notify connect that device is already ready. If we
adjust the disconnection level in notify_connect, the disconnect may have
been triggered at this stage. So we need to change that as early as
possible. The status change of connection is before port reset.
Therefore, we add an api to notify phy the port status changes. In this
stage, the device is not port enable, and it will not trigger
disconnection.
Signed-off-by: Stanley Chang <stanley_chang@realtek.com>
Link: https://lore.kernel.org/r/20230725033318.8361-1-stanley_chang@realtek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expose usb device state to userland as the information is useful in
detecting non-compliant setups and diagnosing enumeration failures.
For example:
- End-to-end signal integrity issues: the device would fail port reset
repeatedly and thus be stuck in POWERED state.
- Charge-only cables (missing D+/D- lines): the device would never enter
POWERED state as the HC would not see any pullup.
What's the status quo?
We do have error logs such as "Cannot enable. Maybe the USB cable is bad?"
to flag potential setup issues, but there's no good way to expose them to
userspace.
Why add a sysfs entry in struct usb_port instead of struct usb_device?
The struct usb_device is not device_add() to the system until it's in
ADDRESS state hence we would miss the first two states. The struct
usb_port is a better place to keep the information because its life
cycle is longer than the struct usb_device that is attached to the port.
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202306042228.e532af6e-oliver.sang@intel.com
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Roy Luo <royluo@google.com>
Message-ID: <20230608015913.1679984-1-royluo@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ever since commit 83e83ecb79a8 ("usb: core: get config and string
descriptors for unauthorized devices") was merged in 2013, there has
been no mechanism for reallocating the rawdescriptors buffers in
struct usb_device after the initial enumeration. Before that commit,
the buffers would be deallocated when a device was deauthorized and
reallocated when it was authorized and enumerated.
This means that the locking in the read_descriptors() routine is not
needed, since the buffers it reads will never be reallocated while the
routine is running. This locking can interfere with user programs
trying to read a hub's descriptors via sysfs while new child devices
of the hub are being initialized, since the hub is locked during this
procedure.
Since the locking in read_descriptors() hasn't been needed for over
nine years, we can remove it.
Reported-and-tested-by: Troels Liebe Bentsen <troels@connectedcars.dk>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
CC: stable@vger.kernel.org
Link: https://lore.kernel.org/r/Y9l+wDTRbuZABzsE@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Texas Instruments TUSB8041 has an autosuspend problem at high
temperature.
If there is not USB traffic, after a couple of ms, the device enters in
autosuspend mode. In this condition the external clock stops working, to
save energy. When the USB activity turns on, ther hub exits the
autosuspend state, the clock starts running again and all works fine.
At ambient temperature all works correctly, but at high temperature,
when the USB activity turns on, the external clock doesn't restart and
the hub disappears from the USB bus.
Disabling the autosuspend mode for this hub solves the issue.
Signed-off-by: Flavio Suligoi <f.suligoi@asem.it>
Cc: stable <stable@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20221219124759.3207032-1-f.suligoi@asem.it
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a broken USB accessory connects to a USB host, usbcore might
keep doing enumeration retries. If the host has a watchdog mechanism,
the kernel panic will happen on the host.
This patch provides an attribute early_stop to limit the numbers of retries
for each port of a hub. If a port was marked with early_stop attribute,
unsuccessful connection attempts will fail quickly. In addition, if an
early_stop port has failed to initialize, it will ignore all future
connection events until early_stop attribute is clear.
Signed-off-by: Ray Chi <raychi@google.com>
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20221107072754.3336357-1-raychi@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Automatic kernel fuzzing revealed a recursive locking violation in
usb-storage:
============================================
WARNING: possible recursive locking detected
5.18.0 #3 Not tainted
--------------------------------------------
kworker/1:3/1205 is trying to acquire lock:
ffff888018638db8 (&us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
but task is already holding lock:
ffff888018638db8 (&us_interface_key[i]){+.+.}-{3:3}, at:
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
...
stack backtrace:
CPU: 1 PID: 1205 Comm: kworker/1:3 Not tainted 5.18.0 #3
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Workqueue: usb_hub_wq hub_event
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2988 [inline]
check_deadlock kernel/locking/lockdep.c:3031 [inline]
validate_chain kernel/locking/lockdep.c:3816 [inline]
__lock_acquire.cold+0x152/0x3ca kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x520 kernel/locking/lockdep.c:5630
__mutex_lock_common kernel/locking/mutex.c:603 [inline]
__mutex_lock+0x14f/0x1610 kernel/locking/mutex.c:747
usb_stor_pre_reset+0x35/0x40 drivers/usb/storage/usb.c:230
usb_reset_device+0x37d/0x9a0 drivers/usb/core/hub.c:6109
r871xu_dev_remove+0x21a/0x270 drivers/staging/rtl8712/usb_intf.c:622
usb_unbind_interface+0x1bd/0x890 drivers/usb/core/driver.c:458
device_remove drivers/base/dd.c:545 [inline]
device_remove+0x11f/0x170 drivers/base/dd.c:537
__device_release_driver drivers/base/dd.c:1222 [inline]
device_release_driver_internal+0x1a7/0x2f0 drivers/base/dd.c:1248
usb_driver_release_interface+0x102/0x180 drivers/usb/core/driver.c:627
usb_forced_unbind_intf+0x4d/0xa0 drivers/usb/core/driver.c:1118
usb_reset_device+0x39b/0x9a0 drivers/usb/core/hub.c:6114
This turned out not to be an error in usb-storage but rather a nested
device reset attempt. That is, as the rtl8712 driver was being
unbound from a composite device in preparation for an unrelated USB
reset (that driver does not have pre_reset or post_reset callbacks),
its ->remove routine called usb_reset_device() -- thus nesting one
reset call within another.
Performing a reset as part of disconnect processing is a questionable
practice at best. However, the bug report points out that the USB
core does not have any protection against nested resets. Adding a
reset_in_progress flag and testing it will prevent such errors in the
future.
Link: https://lore.kernel.org/all/CAB7eexKUpvX-JNiLzhXBDWgfg2T9e9_0Tw4HQ6keN==voRbP0g@mail.gmail.com/
Cc: stable@vger.kernel.org
Reported-and-tested-by: Rondreis <linhaoguo86@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/YwkflDxvg0KWqyZK@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Call onboard_hub_create/destroy_pdevs() from hub_probe/disconnect()
to create/destroy platform devices for onboard USB hubs that may be
connected to the hub. The onboard hubs must have nodes in the
device tree.
onboard_hub_create/destroy_pdevs() are NOPs unless
CONFIG_USB_ONBOARD_HUB=y/m.
Also add a field to struct usb_hub to keep track of the onboard hub
platform devices that are owned by the hub.
Reviewed-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Link: https://lore.kernel.org/r/20220630123445.v24.4.Ic9dd36078f9d803de82ca01a6700c58b8e4de27e@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The host needs to tell the device the exit latencies using the SET_SEL
request before device initiated link powermanagement can be enabled.
The exit latency values do not change after enumeration, it's enough
to set them once. So do like Windows 10 and issue the SET_SEL request
once just before setting the configuration.
This is also the sequence described in USB 3.2 specs "9.1.2 Bus
enumeration". SET_SEL is issued once before the Set Configuration
request, and won't be cleared by the Set Configuration,
Set Interface or ClearFeature (STALL) requests.
Only warm reset, hot reset, set Address 0 clears the exit latencies.
See USB 3.2 section 9.4.14 Table 9-10 Device parameters and events
Add udev->lpm_devinit_allow, and set it if SET_SEL was successful.
If not set, then don't try to enable device initiated LPM
We used to issue a SET_SEL request every time lpm is enabled for either
U1 or U2 link states, meaning a SET_SEL was issued twice after every
Set Configuration and Set Interface requests, easily accumulating to
over 15 SET_SEL requets during a USB3 webcam enumeration.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220506161807.3369439-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In some cases the port of an hub needs to be disabled or switched off
and on again. E.g. when the connected device needs to be re-enumerated.
Or it needs to be explicitly disabled while the rest of the usb tree
stays working.
For this purpose this patch adds an sysfs switch to enable/disable the
port on any hub. In the case the hub is supporting power switching, the
power line will be disabled to the connected device.
When the port gets disabled, the associated device gets disconnected and
removed from the logical usb tree. No further device will be enumerated
on that port until the port gets enabled again.
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Michael Grzeschik <m.grzeschik@pengutronix.de>
Link: https://lore.kernel.org/r/20220607114522.3359148-1-m.grzeschik@pengutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The third argument of usb_maxpacket(): in_out has been deprecated
because it could be derived from the second argument (e.g. using
usb_pipeout(pipe)).
N.B. function usb_maxpacket() was made variadic to accommodate the
transition from the old prototype with three arguments to the new one
with only two arguments (so that no renaming is needed). The variadic
argument is to be removed once all users of usb_maxpacket() get
migrated.
CC: Duncan Sands <duncan.sands@free.fr>
CC: Alan Stern <stern@rowland.harvard.edu>
CC: Olav Kongas <ok@artecdesign.ee>
CC: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Link: https://lore.kernel.org/r/20220317035514.6378-7-mailhol.vincent@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Trying to disable Link Powermanagement (LPM) before port reset is
unnecessary and can cause additional delay if host can't communicate
with the device, which is often the reason why device is reset in the
first place.
usb_disable_lpm() will
- zero usb U1/U2 timeouts for the hub downstream port
- send ENABLE U1/U2 clear feature requests to the connected device.
- increase internal reference count for udev->lpm_disable_count
There is no need to zero U1/U2 hub port timeouts, or clearing the
U1/U2 enable for the connected device before reset. These are set
to default by the reset.
USB 3.1 section 10.2.2 "HUB Downstream port U1/U2 timers" states that:
"the U1 and U2 timeout values for a downstream port reset to the default
values when the port receives a SetPortFeature request for a port reset"
Set the udev->lpm_disable_count to "1" after port reset, which is the
default lpm_disable_count value when allocating udev, representing
disabled LPM.
Cc: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20220216095153.1303105-8-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Unplugging USB device may cause an incorrect warm reset loop and the
port can no longer be used:
[ 143.039019] xhci_hcd 0000:00:14.0: Port change event, 2-3, id 19, portsc: 0x4202c0
[ 143.039025] xhci_hcd 0000:00:14.0: handle_port_status: starting usb2 port polling.
[ 143.039051] hub 2-0:1.0: state 7 ports 10 chg 0000 evt 0008
[ 143.039058] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x4202c0, return 0x4102c0
[ 143.039092] xhci_hcd 0000:00:14.0: clear port3 connect change, portsc: 0x4002c0
[ 143.039096] usb usb2-port3: link state change
[ 143.039099] xhci_hcd 0000:00:14.0: clear port3 link state change, portsc: 0x2c0
[ 143.039101] usb usb2-port3: do warm reset
[ 143.096736] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2b0, return 0x2b0
[ 143.096751] usb usb2-port3: not warm reset yet, waiting 50ms
[ 143.131500] xhci_hcd 0000:00:14.0: Can't queue urb, port error, link inactive
[ 143.138260] xhci_hcd 0000:00:14.0: Port change event, 2-3, id 19, portsc: 0x2802a0
[ 143.138263] xhci_hcd 0000:00:14.0: handle_port_status: starting usb2 port polling.
[ 143.160756] xhci_hcd 0000:00:14.0: Get port status 2-3 read: 0x2802a0, return 0x3002a0
[ 143.160798] usb usb2-port3: not warm reset yet, waiting 200ms
The port status is PP=1, CCS=0, PED=0, PLS=Inactive, which is Error
state per "USB3 Root Hub Port State Machine". It's reasonable to perform
warm reset several times, but if the port is still not enabled after
many attempts, consider it's gone and treat it as disconnected.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20220120070518.1643873-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Bugzilla #213839 reports a 7-port hub that doesn't work properly when
devices are plugged into some of the ports; the kernel goes into an
unending disconnect/reinitialize loop as shown in the bug report.
This "7-port hub" comprises two four-port hubs with one plugged into
the other; the failures occur when a device is plugged into one of the
downstream hub's ports. (These hubs have other problems too. For
example, they bill themselves as USB-2.0 compliant but they only run
at full speed.)
It turns out that the failures are caused by bugs in both the kernel
and the hub. The hub's bug is that it reports a different
bmAttributes value in its configuration descriptor following a remote
wakeup (0xe0 before, 0xc0 after -- the wakeup-support bit has
changed).
The kernel's bug is inside the hub driver's resume handler. When
hub_activate() sees that one of the hub's downstream ports got a
wakeup request from a child device, it notes this fact by setting the
corresponding bit in the hub->change_bits variable. But this variable
is meant for connection changes, not wakeup events; setting it causes
the driver to believe the downstream port has been disconnected and
then connected again (in addition to having received a wakeup
request).
Because of this, the hub driver then tries to check whether the device
currently plugged into the downstream port is the same as the device
that had been attached there before. Normally this check succeeds and
wakeup handling continues with no harm done (which is why the bug
remained undetected until now). But with these dodgy hubs, the check
fails because the config descriptor has changed. This causes the hub
driver to reinitialize the child device, leading to the
disconnect/reinitialize loop described in the bug report.
The proper way to note reception of a downstream wakeup request is
to set a bit in the hub->event_bits variable instead of
hub->change_bits. That way the hub driver will realize that something
has happened to the port but will not think the port and child device
have been disconnected. This patch makes that change.
Cc: <stable@vger.kernel.org>
Tested-by: Jonathan McDowell <noodles@earth.li>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/YdCw7nSfWYPKWQoD@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a new USB device gets plugged to nested hubs, the affected hub,
which connects to usb 2-1.4-port2, doesn't report there's any change,
hence the nested hubs go back to runtime suspend like nothing happened:
[ 281.032951] usb usb2: usb wakeup-resume
[ 281.032959] usb usb2: usb auto-resume
[ 281.032974] hub 2-0:1.0: hub_resume
[ 281.033011] usb usb2-port1: status 0263 change 0000
[ 281.033077] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.049797] usb 2-1: usb wakeup-resume
[ 281.069800] usb 2-1: Waited 0ms for CONNECT
[ 281.069810] usb 2-1: finish resume
[ 281.070026] hub 2-1:1.0: hub_resume
[ 281.070250] usb 2-1-port4: status 0203 change 0000
[ 281.070272] usb usb2-port1: resume, status 0
[ 281.070282] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[ 281.089813] usb 2-1.4: usb wakeup-resume
[ 281.109792] usb 2-1.4: Waited 0ms for CONNECT
[ 281.109801] usb 2-1.4: finish resume
[ 281.109991] hub 2-1.4:1.0: hub_resume
[ 281.110147] usb 2-1.4-port2: status 0263 change 0000
[ 281.110234] usb 2-1-port4: resume, status 0
[ 281.110239] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[ 281.110266] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.110426] hub 2-1.4:1.0: hub_suspend
[ 281.110565] usb 2-1.4: usb auto-suspend, wakeup 1
[ 281.130998] hub 2-1:1.0: hub_suspend
[ 281.137788] usb 2-1: usb auto-suspend, wakeup 1
[ 281.142935] hub 2-0:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.177828] usb 2-1: usb wakeup-resume
[ 281.197839] usb 2-1: Waited 0ms for CONNECT
[ 281.197850] usb 2-1: finish resume
[ 281.197984] hub 2-1:1.0: hub_resume
[ 281.198203] usb 2-1-port4: status 0203 change 0000
[ 281.198228] usb usb2-port1: resume, status 0
[ 281.198237] hub 2-1:1.0: state 7 ports 4 chg 0010 evt 0000
[ 281.217835] usb 2-1.4: usb wakeup-resume
[ 281.237834] usb 2-1.4: Waited 0ms for CONNECT
[ 281.237845] usb 2-1.4: finish resume
[ 281.237990] hub 2-1.4:1.0: hub_resume
[ 281.238067] usb 2-1.4-port2: status 0263 change 0000
[ 281.238148] usb 2-1-port4: resume, status 0
[ 281.238152] usb 2-1-port4: status 0203, change 0000, 10.0 Gb/s
[ 281.238166] hub 2-1.4:1.0: state 7 ports 4 chg 0000 evt 0000
[ 281.238385] hub 2-1.4:1.0: hub_suspend
[ 281.238523] usb 2-1.4: usb auto-suspend, wakeup 1
[ 281.258076] hub 2-1:1.0: hub_suspend
[ 281.265744] usb 2-1: usb auto-suspend, wakeup 1
[ 281.285976] hub 2-0:1.0: hub_suspend
[ 281.285988] usb usb2: bus auto-suspend, wakeup 1
USB 3.2 spec, 9.2.5.4 "Changing Function Suspend State" says that "If
the link is in a non-U0 state, then the device must transition the link
to U0 prior to sending the remote wake message", but the hub only
transits the link to U0 after signaling remote wakeup.
So be more forgiving and use a 20ms delay to let the link transit to U0
for remote wakeup.
Suggested-by: Alan Stern <stern@rowland.harvard.edu>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Link: https://lore.kernel.org/r/20211215120108.336597-1-kai.heng.feng@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The wait_for_connected() function doesn't modify "*port1" and there is
no need to pass a pointer. Just pass the int itself.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20211210142028.GB18906@kili
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During disconnect USB-3 ports often go via SS.Inactive link error state
before the missing terminations are noticed, and link finally goes to
RxDetect state
Avoid immediately warm-resetting ports in SS.Inactive state.
Let ports settle for a while and re-read the link status a few times 20ms
apart to see if the ports transitions out of SS.Inactive.
According to USB 3.x spec 7.5.2, a port in SS.Inactive should
automatically check for missing far-end receiver termination every
12 ms (SSInactiveQuietTimeout)
The futile multiple warm reset retries of a disconnected device takes
a lot of time, also the resetting of a removed devices has caused cases
where the reset bit got stuck for a long time on xHCI roothub.
This lead to issues in detecting new devices connected to the same port
shortly after.
Tested-by: Mark Pearson <markpearson@lenovo.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211210111653.1378381-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix the circular lock dependency and unbalanced unlock of addess0_mutex
introduced when fixing an address0_mutex enumeration retry race in commit
ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0 race")
Make sure locking order between port_dev->status_lock and address0_mutex
is correct, and that address0_mutex is not unlocked in hub_port_connect
"done:" codepath which may be reached without locking address0_mutex
Fixes: 6ae6dc22d2d1 ("usb: hub: Fix usb enumeration issue due to address0 race")
Cc: <stable@vger.kernel.org>
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211123101656.1113518-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
xHC hardware can only have one slot in default state with address 0
waiting for a unique address at a time, otherwise "undefined behavior
may occur" according to xhci spec 5.4.3.4
The address0_mutex exists to prevent this across both xhci roothubs.
If hub_port_init() fails, it may unlock the mutex and exit with a xhci
slot in default state. If the other xhci roothub calls hub_port_init()
at this point we end up with two slots in default state.
Make sure the address0_mutex protects the slot default state across
hub_port_init() retries, until slot is addressed or disabled.
Note, one known minor case is not fixed by this patch.
If device needs to be reset during resume, but fails all hub_port_init()
retries in usb_reset_and_verify_device(), then it's possible the slot is
still left in default state when address0_mutex is unlocked.
Cc: <stable@vger.kernel.org>
Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel")
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211115221630.871204-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The device initiated link power management U1/U2 states should not be
enabled in case the system exit latency plus one bus interval (125us) is
greater than the shortest service interval of any periodic endpoint.
This is the case for both U1 and U2 sytstem exit latencies and link states.
See USB 3.2 section 9.4.9 "Set Feature" for more details
Note, before this patch the host and device initiated U1/U2 lpm states
were both enabled with lpm. After this patch it's possible to end up with
only host inititated U1/U2 lpm in case the exit latencies won't allow
device initiated lpm.
If this case we still want to set the udev->usb3_lpm_ux_enabled flag so
that sysfs users can see the link may go to U1/U2.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210715150122.1995966-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Maximum Exit Latency (MEL) value is used by host to know how much in
advance it needs to start waking up a U1/U2 suspended link in order to
service a periodic transfer in time.
Current MEL calculation only includes the time to wake up the path from
U1/U2 to U0. This is called tMEL1 in USB 3.1 section C 1.5.2
Total MEL = tMEL1 + tMEL2 +tMEL3 + tMEL4 which should additinally include:
- tMEL2 which is the time it takes for PING message to reach device
- tMEL3 time for device to process the PING and submit a PING_RESPONSE
- tMEL4 time for PING_RESPONSE to traverse back upstream to host.
Add the missing tMEL2, tMEL3 and tMEL4 to MEL calculation.
Cc: <stable@kernel.org> # v3.5
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210715150122.1995966-1-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'v5.13-rc7' into usb-next
We need the USB fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Cypress CY7C65632 appears to have an issue with auto suspend and
detecting devices, not too dissimilar to the SMSC 5534B hub. It is
easiest to reproduce by connecting multiple mass storage devices to
the hub at the same time. On a Lenovo Yoga, around 1 in 3 attempts
result in the devices not being detected. It is however possible to
make them appear using lsusb -v.
Disabling autosuspend for this hub resolves the issue.
Fixes: 1208f9e1d758 ("USB: hub: Fix the broken detection of USB3 device in SMSC hub")
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Link: https://lore.kernel.org/r/20210614155524.2228800-1-andrew@lunn.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move the "removable" attribute from USB to core in order to allow it to be
supported by other subsystem / buses. Individual buses that want to support
this attribute can populate the removable property of the device while
enumerating it with the 3 possible values -
- "unknown"
- "fixed"
- "removable"
Leaving the field unchanged (i.e. "not supported") would mean that the
attribute would not show up in sysfs for that device. The UAPI (location,
symantics etc) for the attribute remains unchanged.
Move the "removable" attribute from USB to the device core so it can be
used by other subsystems / buses.
By default, devices do not have a "removable" attribute in sysfs.
If a subsystem or bus driver wants to support a "removable" attribute, it
should call device_set_removable() before calling device_register() or
device_add(), e.g.:
device_set_removable(dev, DEVICE_REMOVABLE);
device_register(dev);
The possible values and the resulting sysfs attribute contents are:
DEVICE_REMOVABLE_UNKNOWN -> "unknown"
DEVICE_REMOVABLE -> "removable"
DEVICE_FIXED -> "fixed"
Convert the USB "removable" attribute to use this new device core
functionality. There should be no user-visible change in the location or
semantics of attribute for USB devices.
Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rajat Jain <rajatja@google.com>
Link: https://lore.kernel.org/r/20210524171812.18095-1-rajatja@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
On the Realtek high-speed Hub(0bda:5487), the port which has wakeup
enabled_descendants will sometimes timeout when setting PORT_SUSPEND
feature. After checking the PORT_SUSPEND bit in wPortStatus, it is
already set which means the port has been suspended. We should treat
it suspended to make sure it will be resumed correctly.
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chris Chiu <chris.chiu@canonical.com>
Link: https://lore.kernel.org/r/20210514045405.5261-2-chris.chiu@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This may happen if the port becomes resume status exactly
when usb_port_resume() gets port status, it still need provide
a TRSMCRY time before access the device.
CC: <stable@vger.kernel.org>
Reported-by: Tianping Fang <tianping.fang@mediatek.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Chunfeng Yun <chunfeng.yun@mediatek.com>
Link: https://lore.kernel.org/r/20210512020738.52961-1-chunfeng.yun@mediatek.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pm_runtime_get_sync will increment pm usage counter even it failed.
thus a pairing decrement is needed.
Fix it by replacing it with pm_runtime_resume_and_get to keep usage
counter balanced.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Bixuan Cui <cuibixuan@huawei.com>
Link: https://lore.kernel.org/r/20210408130831.56239-1-cuibixuan@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The usage of in_interrupt() in drivers is phased out for various reasons.
Various comments use !in_interrupt() to describe calling context for
functions which might sleep. That's wrong because the calling context has
to be preemptible task context, which is not what !in_interrupt()
describes.
Replace !in_interrupt() with more accurate plain text descriptions.
The comment for usb_hcd_poll_rh_status() is misleading as this function is
called from all kinds of contexts including preemptible task
context. Remove it as there is obviously no restriction.
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Cc: linux-usb@vger.kernel.org
Link: https://lore.kernel.org/r/20201019101110.851821025@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Description based on one by Yasushi Asano:
According to 6.7.22 A-UUT “Device No Response” for connection timeout
of USB OTG and EH automated compliance plan v1.2, enumeration failure
has to be detected within 30 seconds. However, the old and new
enumeration schemes each make a total of 12 attempts, and each attempt
can take 5 seconds to time out, so the PET test fails.
This patch adds a new Kconfig option (CONFIG_USB_FEW_INIT_RETRIES);
when the option is set all the initialization retry loops except the
outermost are reduced to a single iteration. This reduces the total
number of attempts to four, allowing Linux hosts to pass the PET test.
The new option is disabled by default to preserve the existing
behavior. The reduced number of retries may fail to initialize a few
devices that currently do work, but for the most part there should be
no change. And in cases where the initialization does fail, it will
fail much more quickly.
Reported-and-tested-by: yasushi asano <yazzep@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200928152217.GB134701@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The SET_CONFIG_TRIES macro in hub.c is badly named; it controls the
number of port-initialization retry attempts rather than the number of
Set-Configuration attempts. Furthermore, the USE_NEW_SCHEME macro and
use_new_scheme() function are written in a very confusing manner,
making it almost impossible to figure out exactly what they do or
check that they are correct.
This patch renames SET_CONFIG_TRIES to PORT_INIT_TRIES, removes
USE_NEW_SCHEME entirely, and rewrites use_new_scheme() to be much more
transparent, with added comments explaining how it works. The patch
also pulls the single call site of use_new_scheme() out from the
Get-Descriptor retry loop (where it returns the same value each time)
and renames the local variable used to store the result.
The overall effect is a minor cleanup. However, there is one
functional change: If the "use_both_schemes" module parameter isn't
set (by default it is set), the existing code does only two retry
iterations. After this patch it will always perform four, regardless
of the parameter's value.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200928152050.GA134701@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit d6a499249543356002a1efbb26254c7272e62f4c.
Control messages are needed in contexts when memory allocations
are restricted, such as handling device resets and runtime PM.
For this reason the control message API internally uses GFP_NOIO.
This is a band aid introduced because when we recognized the issue,
the call chains were highly convoluted. Continuing this trend
is not a good idea.
So I am shooting the whole kennel here.
Signed-off-by: Oliver Neukum <oneukum@suse.com>
Link: https://lore.kernel.org/r/20200923134348.23862-2-oneukum@suse.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are a few calls to usb_control_msg() that can be converted to use
usb_control_msg_send() instead, so do that in order to make the error
checking a bit simpler and the code smaller.
Reviewed-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20200914153756.3412156-5-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Rename the list of specific devices that an OTG device could support to
make it more obvious as to what this list is for and what it is doing.
Also rename the configuration option to make it more obvious as well.
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Paul Burton <paulburton@kernel.org>
Cc: "Diego Elio Pettenò" <flameeyes@flameeyes.com>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: "Philippe Mathieu-Daudé" <f4bug@amsat.org>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Qi Zhou <atmgnd@outlook.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Hardik Gajjar <hgajjar@de.adit-jv.com>
Cc: Harry Pan <harry.pan@intel.com>
Cc: David Heinzelmann <heinzelmann.david@gmail.com>
Cc: Nishad Kamdar <nishadkamdar@gmail.com>
Link: https://lore.kernel.org/r/20200618094300.1887727-9-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The USB OTG code has the ability to disable external hubs, but the
configuration option for it is oddly named. Rename it to be more
obvious as to what it does.
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Bin Liu <b-liu@ti.com>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Eugeniu Rosca <erosca@de.adit-jv.com>
Cc: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: David Heinzelmann <heinzelmann.david@gmail.com>
Cc: "Lee, Chiasheng" <chiasheng.lee@intel.com>
Cc: Keiya Nobuta <nobuta.keiya@fujitsu.com>
Cc: Hardik Gajjar <hgajjar@de.adit-jv.com>
Link: https://lore.kernel.org/r/20200618094300.1887727-3-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix the following coccicheck warning:
drivers/usb/core/hub.c:95:12-28: WARNING: Assignment of 0/1 to bool
variable
Signed-off-by: Jason Yan <yanaijie@huawei.com>
Link: https://lore.kernel.org/r/20200426094147.23467-1-yanaijie@huawei.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit bd0e6c9614b9 ("usb: hub: try old enumeration scheme first for
high speed devices") changed the way the hub driver enumerates
high-speed devices. Instead of using the "new" enumeration scheme
first and switching to the "old" scheme if that doesn't work, we start
with the "old" scheme. In theory this is better because the "old"
scheme is slightly faster -- it involves resetting the device only
once instead of twice.
However, for a long time Windows used only the "new" scheme. Zeng Tao
said that Windows 8 and later use the "old" scheme for high-speed
devices, but apparently there are some devices that don't like it.
William Bader reports that the Ricoh webcam built into his Sony Vaio
laptop not only doesn't enumerate under the "old" scheme, it gets hung
up so badly that it won't then enumerate under the "new" scheme! Only
a cold reset will fix it.
Therefore we will revert the commit and go back to trying the "new"
scheme first for high-speed devices.
Reported-and-tested-by: William Bader <williambader@hotmail.com>
Ref: https://bugzilla.kernel.org/show_bug.cgi?id=207219
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Fixes: bd0e6c9614b9 ("usb: hub: try old enumeration scheme first for high speed devices")
CC: Zeng Tao <prime.zeng@hisilicon.com>
CC: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2004221611230.11262-100000@iolanthe.rowland.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
