kernel.git/drivers/usb/core/hub.c, branch linux-4.4.y

usb: hub: Add delay for SuperSpeed hub resume to let links transit to U0

2022-01-27T07:46:17Z

[ Upstream commit 00558586382891540c59c9febc671062425a6e47 ] 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 Acked-by: Alan Stern Signed-off-by: Kai-Heng Feng Link: https://lore.kernel.org/r/20211215120108.336597-1-kai.heng.feng@canonical.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

USB: core: Fix bug in resuming hub's handling of wakeup requests

2022-01-27T07:46:12Z

commit 0f663729bb4afc92a9986b66131ebd5b8a9254d1 upstream. 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: Tested-by: Jonathan McDowell Signed-off-by: Alan Stern Link: https://lore.kernel.org/r/YdCw7nSfWYPKWQoD@rowland.harvard.edu Signed-off-by: Greg Kroah-Hartman

usb: hub: Fix locking issues with address0_mutex

2021-12-08T07:44:05Z

commit 6cca13de26eea6d32a98d96d916a048d16a12822 upstream. 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: Reported-by: Marek Szyprowski Tested-by: Hans de Goede Tested-by: Marek Szyprowski Acked-by: Hans de Goede Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20211123101656.1113518-1-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: hub: Fix usb enumeration issue due to address0 race

2021-12-08T07:44:05Z

commit 6ae6dc22d2d1ce6aa77a6da8a761e61aca216f8b upstream. 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: Fixes: 638139eb95d2 ("usb: hub: allow to process more usb hub events in parallel") Signed-off-by: Mathias Nyman Link: https://lore.kernel.org/r/20211115221630.871204-1-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: hub: Disable USB 3 device initiated lpm if exit latency is too high

2021-07-28T07:12:36Z

commit 1b7f56fbc7a1b66967b6114d1b5f5a257c3abae6 upstream. 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 Cc: stable Link: https://lore.kernel.org/r/20210715150122.1995966-2-mathias.nyman@linux.intel.com Signed-off-by: Greg Kroah-Hartman

usb: core: hub: fix race condition about TRSMRCY of resume

2021-05-22T08:38:29Z

commit 975f94c7d6c306b833628baa9aec3f79db1eb3a1 upstream. 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: Reported-by: Tianping Fang Acked-by: Alan Stern Signed-off-by: Chunfeng Yun Link: https://lore.kernel.org/r/20210512020738.52961-1-chunfeng.yun@mediatek.com Signed-off-by: Greg Kroah-Hartman

USB: hub: Fix handling of connect changes during sleep

2020-05-02T15:20:45Z

commit 9f952e26295d977dbfc6fedeaf8c4f112c818d37 upstream. Commit 8099f58f1ecd ("USB: hub: Don't record a connect-change event during reset-resume") wasn't very well conceived. The problem it tried to fix was that if a connect-change event occurred while the system was asleep (such as a device disconnecting itself from the bus when it is suspended and then reconnecting when it resumes) requiring a reset-resume during the system wakeup transition, the hub port's change_bit entry would remain set afterward. This would cause the hub driver to believe another connect-change event had occurred after the reset-resume, which was wrong and would lead the driver to send unnecessary requests to the device (which could interfere with a firmware update). The commit tried to fix this by not setting the change_bit during the wakeup. But this was the wrong thing to do; it means that when a device is unplugged while the system is asleep, the hub driver doesn't realize anything has happened: The change_bit flag which would tell it to handle the disconnect event is clear. The commit needs to be reverted and the problem fixed in a different way. Fortunately an alternative solution was noted in the commit's Changelog: We can continue to set the change_bit entry in hub_activate() but then clear it when a reset-resume occurs. That way the the hub driver will see the change_bit when a device is disconnected but won't see it when the device is still present. That's what this patch does. Reported-and-tested-by: Peter Chen Signed-off-by: Alan Stern Fixes: 8099f58f1ecd ("USB: hub: Don't record a connect-change event during reset-resume") Tested-by: Paul Zimmerman CC: Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2004221602480.11262-100000@iolanthe.rowland.org Signed-off-by: Greg Kroah-Hartman

usb: core: hub: do error out if usb_autopm_get_interface() fails

2020-03-11T06:51:17Z

commit 60e3f6e4ac5b0fda43dad01c32e09409ec710045 upstream. Reviewing a fresh portion of coverity defects in USB core (specifically CID 1458999), Alan Stern noted below in [1]: On Tue, Feb 25, 2020 at 02:39:23PM -0500, Alan Stern wrote: > A revised search finds line 997 in drivers/usb/core/hub.c and lines > 216, 269 in drivers/usb/core/port.c. (I didn't try looking in any > other directories.) AFAICT all three of these should check the > return value, although a error message in the kernel log probably > isn't needed. Factor out the usb_remove_device() change into a standalone patch to allow conflict-free integration on top of the earliest stable branches. [1] https://lore.kernel.org/lkml/Pine.LNX.4.44L0.2002251419120.1485-100000@iolanthe.rowland.org Fixes: 253e05724f9230 ("USB: add a "remove hardware" sysfs attribute") Cc: stable@vger.kernel.org # v2.6.33+ Suggested-by: Alan Stern Signed-off-by: Eugeniu Rosca Acked-by: Alan Stern Link: https://lore.kernel.org/r/20200226175036.14946-2-erosca@de.adit-jv.com Signed-off-by: Greg Kroah-Hartman

USB: hub: Don't record a connect-change event during reset-resume

2020-02-28T14:39:12Z

commit 8099f58f1ecddf4f374f4828a3dff8397c7cbd74 upstream. Paul Zimmerman reports that his USB Bluetooth adapter sometimes crashes following system resume, when it receives a Get-Device-Descriptor request while it is busy doing something else. Such a request was added by commit a4f55d8b8c14 ("usb: hub: Check device descriptor before resusciation"). It gets sent when the hub driver's work thread checks whether a connect-change event on an enabled port really indicates a new device has been connected, as opposed to an old device momentarily disconnecting and then reconnecting (which can happen with xHCI host controllers, since they automatically enable connected ports). The same kind of thing occurs when a port's power session is lost during system suspend. When the system wakes up it sees a connect-change event on the port, and if the child device's persist_enabled flag was set then hub_activate() sets the device's reset_resume flag as well as the port's bit in hub->change_bits. The reset-resume code then takes responsibility for checking that the same device is still attached to the port, and it does this as part of the device's resume pathway. By the time the hub driver's work thread starts up again, the device has already been fully reinitialized and is busy doing its own thing. There's no need for the work thread to do the same check a second time, and in fact this unnecessary check is what caused the problem that Paul observed. Note that performing the unnecessary check is not actually a bug. Devices are supposed to be able to send descriptors back to the host even when they are busy doing something else. The underlying cause of Paul's problem lies in his Bluetooth adapter. Nevertheless, we shouldn't perform the same check twice in a row -- and as a nice side benefit, removing the extra check allows the Bluetooth adapter to work more reliably. The work thread performs its check when it sees that the port's bit is set in hub->change_bits. In this situation that bit is interpreted as though a connect-change event had occurred on the port _after_ the reset-resume, which is not what actually happened. One possible fix would be to make the reset-resume code clear the port's bit in hub->change_bits. But it seems simpler to just avoid setting the bit during hub_activate() in the first place. That's what this patch does. (Proving that the patch is correct when CONFIG_PM is disabled requires a little thought. In that setting hub_activate() will be called only for initialization and resets, since there won't be any resumes or reset-resumes. During initialization and hub resets the hub doesn't have any child devices, and so this code path never gets executed.) Reported-and-tested-by: Paul Zimmerman Signed-off-by: Alan Stern Link: https://marc.info/?t=157949360700001&r=1&w=2 CC: David Heinzelmann CC: Link: https://lore.kernel.org/r/Pine.LNX.4.44L0.2001311037460.1577-100000@iolanthe.rowland.org Signed-off-by: Greg Kroah-Hartman

usb: core: hub: Improved device recognition on remote wakeup

2020-01-23T07:18:39Z

commit 9c06ac4c83df6d6fbdbf7488fbad822b4002ba19 upstream. If hub_activate() is called before D+ has stabilized after remote wakeup, the following situation might occur: __ ___________________ / \ / D+ __/ \__/ Hub _______________________________ | ^ ^ ^ | | | | Host _____v__|___|___________|______ | | | | | | | \-- Interrupt Transfer (*3) | | \-- ClearPortFeature (*2) | \-- GetPortStatus (*1) \-- Host detects remote wakeup - D+ goes high, Host starts running by remote wakeup - D+ is not stable, goes low - Host requests GetPortStatus at (*1) and gets the following hub status: - Current Connect Status bit is 0 - Connect Status Change bit is 1 - D+ stabilizes, goes high - Host requests ClearPortFeature and thus Connect Status Change bit is cleared at (*2) - After waiting 100 ms, Host starts the Interrupt Transfer at (*3) - Since the Connect Status Change bit is 0, Hub returns NAK. In this case, port_event() is not called in hub_event() and Host cannot recognize device. To solve this issue, flag change_bits even if only Connect Status Change bit is 1 when got in the first GetPortStatus. This issue occurs rarely because it only if D+ changes during a very short time between GetPortStatus and ClearPortFeature. However, it is fatal if it occurs in embedded system. Signed-off-by: Keiya Nobuta Cc: stable Acked-by: Alan Stern Link: https://lore.kernel.org/r/20200109051448.28150-1-nobuta.keiya@fujitsu.com Signed-off-by: Greg Kroah-Hartman