On Mon, Jan 29, 2018 at 07:21:09PM +0100, Markus Demleitner wrote: > Hi, > > A while ago I opened bug #197863 in the kernel bugzilla: > > https://bugzilla.kernel.org/show_bug.cgi?id=197863 > > Essentially, xhci_hcd on a resume from RAM takes several seconds on a > Thinkpad X240 that is equipped with a Sierra LTE modem after an > upgrade to 4.13: > > On Mon, Nov 20, 2017 at 11:24:09AM +0000, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > > https://bugzilla.kernel.org/show_bug.cgi?id=197863 > > > > --- Comment #2 from Greg Kroah-Hartman (greg@xxxxxxxxx) --- > > On Mon, Nov 20, 2017 at 09:02:46AM +0000, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx > > wrote: > > > I think your speculation is right, the xhci has taken too much time for a > > > reset: > > > [ 39.292052] usb 1-4: reset high-speed USB device number 2 using xhci_hcd > > > [ 45.812046] usb 1-4: device descriptor read/64, error -110 > > > [ 46.262082] usb 1-7: reset full-speed USB device number 3 using xhci_hcd > > > I don't know if it should be reset in this case, let me switch to usb > > > component for suggestion. > > > > All USB bugs should be sent to the linux-usb@xxxxxxxxxxxxxxx mailing > > list, and not entered into bugzilla. Please bring this issue up there, > > if it is still a problem in the latest kernel release. > > The trouble persists in 4.15.0, and wakeup keeps being fast in 4.12.X. > > I have just looked at things a bit more closely, and it would seem > the changes are due to the USB subsystem blocking until the (slow) > LTE modem sends an all clear. > > Here's a dmesg excerpt from 4.15.0 slow resume: > > > [ 417.234716] ACPI: Low-level resume complete > ...about 30 lines of non-USB jabber elided here... > [ 419.184328] usb usb1: root hub lost power or was reset > [ 419.184332] usb usb2: root hub lost power or was reset > [ 419.463469] usb 3-1: reset high-speed USB device number 2 using ehci-pci > [ 419.583449] usb 1-8: reset high-speed USB device number 4 using xhci_hcd > [ 419.588769] psmouse serio1: synaptics: queried min coordinates: x [1232..], y [1216..] > [ 419.821258] restoring control 00000000-0000-0000-0000-000000000101/0/2 > [ 419.913513] usb 1-4: reset high-speed USB device number 9 using xhci_hcd > ...this is when the system hangs; the screen is on, but now wakeup > actions are executed until... > [ 427.343486] usb 1-4: device descriptor read/64, error -110 > [ 427.662438] OOM killer enabled. > [ 427.662440] Restarting tasks ... done. > [ 427.683062] PM: suspend exit > > If you look at the corresponding sequence in 4.12.2: > > [ 31.678001] usb 1-4: reset high-speed USB device number 2 using xhci_hcd > [ 31.848202] usb 1-4: device firmware changed > [ 31.988048] usb 1-7: reset full-speed USB device number 3 using xhci_hcd > [ 32.159069] PM: resume of devices complete after 1170.527 msecs > [ 32.159546] OOM killer enabled. > [ 32.159548] Restarting tasks ... > [ 32.159650] usb 1-4: USB disconnect, device number 2 > [ 32.162274] done. > [ 32.297920] usb 1-4: new high-speed USB device number 5 using xhci_hcd > [ 32.469119] usb 1-4: New USB device found, idVendor=8087, idProduct=0716 > [ 32.469124] usb 1-4: New USB device strings: Mfr=0, Product=0, SerialNumber=0 > [ 35.639922] usb 1-4: USB disconnect, device number 5 > [ 38.438173] usb 1-4: new high-speed USB device number 6 using xhci_hcd > [ 38.616527] usb 1-4: New USB device found, idVendor=1199, idProduct=a001 > [ 38.616535] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 > [ 38.616539] usb 1-4: Product: Sierra Wireless EM7345 4G LTE > [ 38.616543] usb 1-4: Manufacturer: Sierra Wireless Inc. > [ 38.616545] usb 1-4: SerialNumber: 013937002544516 > > ...it seems that the resume of the Sierra card happens > "aynchronously", if you will. In the "slow" cases, I just notice, no > messages about the Sierra Wireless card appear in dmesg, but the > modem still works. > > Now, interestingly, there are quick resumes in 4.15.0, too, now and > then. In that case, things look pretty much like on 4.12.2. Here's > a 4.15.0 fast resume example: > > [ 873.127570] usb 1-4: device firmware changed > [ 873.277351] usb 1-8: reset high-speed USB device number 4 using xhci_hcd > [ 873.515141] restoring control 00000000-0000-0000-0000-000000000101/0/2 > [ 873.583238] OOM killer enabled. > [ 873.583240] Restarting tasks ... > [ 873.583339] usb 1-4: USB disconnect, device number 10 > [ 873.586356] done. > [ 873.604420] PM: suspend exit > [ 873.737283] usb 1-4: new high-speed USB device number 11 using xhci_hcd > [ 880.867398] usb 1-4: device descriptor read/64, error -110 > [ 881.175558] usb 1-4: New USB device found, idVendor=1199, idProduct=a001 > [ 881.175563] usb 1-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3 > [ 881.175566] usb 1-4: Product: Sierra Wireless EM7345 4G LTE > [ 881.175568] usb 1-4: Manufacturer: Sierra Wireless Inc. > [ 881.175570] usb 1-4: SerialNumber: 013937002544516 > > Any guess what might be behind this? Any chance you can run 'git bisect' to find the offending commit for this issue? thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
