46fdba26cd
[ 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 <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> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.