Hello Alan, thanks for bearing with me. > I'm not sure what you mean by that. Everything we have been discussing > is in hub.c, not usb.c. Argh. That means I messed up the dynamic debug setting that was supposed to enable the additional log statements. Luckily, I didn't need it anyway, because we could see the entry/exit output even so. > The boot sequence isn't enough. I need to see what happens when the > system freezes. And I'd like to give you that information, but there is no output before the freeze. On the plus side, I think I can tell you why. You've given me a new way to trigger the freeze on a "bad" kernel: > echo 0000:00:1d.0 >/sys/bus/pci/drivers/ehci-pci/unbind The output you are looking for would appear on the bind, correct? But the system already freezes on the unbind. Is the workqueue that was changed from ordered to unordered involved at that point, too? > In the "good" kernel, the 1-1 device is probed _before_ the devices on > bus 2, whereas in the "bad" kernel it is probed _after_ them. That > could make a difference; the buses are supposed to be independent but > they might not be. However, this is not relevant to the main problem, > which is the hangs. > > (You can test this hypothesis by booting the "good" kernel, and after > [...] > If the guess is correct, the probes following this bind should > succeed.) Your guess is correct. If the order of the probes is relevant, although it shouldn't be, maybe the order on shutdown/unbind also plays a role? > Also, the log doesn't go all the way back to the initial boot. > Probably the kernel's log buffer overflowed and wrapped around because > of all the useless systemd output. Is there any way you can tell > systemd not to write its output to the kernel log buffer? Yes, "systemd.log_target=null" does the trick. See below for the new logs. Coming from another angle: Is it possible to tell the kernel to ignore the USB hub that causes my problems, so it won't get probed at all? I'll need the machine in working order from October through December, and I'd rather have it on a current kernel with special boot parameters than on a backlevel kernel, or on one I have to patch myself. Thanks and cheers, Roland > grep -i -e 'usb\|hub' dmesg.nosystemd.txt # for the complete file, see # https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1485057/+attachment/4458181/+files/dmesg.nosystemd.txt [ 0.577810] ACPI: Power Resource [USBC] (on) [ 0.819230] ACPI: bus type USB registered [ 0.819270] usbcore: registered new interface driver usbfs [ 0.819295] usbcore: registered new interface driver hub [ 0.819328] usbcore: registered new device driver usb [ 1.594144] ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver [ 1.606441] ehci-pci 0000:00:1d.0: new USB bus registered, assigned bus number 1 [ 1.641436] ehci-pci 0000:00:1d.0: USB 2.0 started, EHCI 1.00 [ 1.645754] usb usb1: udev 1, busnum 1, minor = 0 [ 1.649921] usb usb1: New USB device found, idVendor=1d6b, idProduct=0002 [ 1.654112] usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 1.662300] usb usb1: Product: EHCI Host Controller [ 1.666540] usb usb1: Manufacturer: Linux 3.17.0-rc6-p ehci_hcd [ 1.670728] usb usb1: SerialNumber: 0000:00:1d.0 [ 1.675206] hub 1-0:1.0: USB hub found [ 1.679398] hub 1-0:1.0: 8 ports detected [ 1.683541] hub 1-0:1.0: standalone hub [ 1.687602] hub 1-0:1.0: no power switching (usb 1.0) [ 1.691577] hub 1-0:1.0: individual port over-current protection [ 1.695522] hub 1-0:1.0: power on to power good time: 20ms [ 1.699445] hub 1-0:1.0: local power source is good [ 1.703476] hub 1-0:1.0: trying to enable port power on non-switchable hub [ 1.711279] ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver [ 1.723132] uhci_hcd: USB Universal Host Controller Interface driver [ 1.731406] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 2 [ 1.748268] usb usb2: udev 1, busnum 2, minor = 128 [ 1.752304] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002 [ 1.756309] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 1.764245] usb usb2: Product: xHCI Host Controller [ 1.768365] usb usb2: Manufacturer: Linux 3.17.0-rc6-p xhci_hcd [ 1.772497] usb usb2: SerialNumber: 0000:00:14.0 [ 1.776978] hub 2-0:1.0: USB hub found [ 1.781100] hub 2-0:1.0: 6 ports detected [ 1.785081] hub 2-0:1.0: standalone hub [ 1.789022] hub 2-0:1.0: no power switching (usb 1.0) [ 1.792895] hub 2-0:1.0: individual port over-current protection [ 1.796744] hub 2-0:1.0: Single TT [ 1.800630] hub 2-0:1.0: TT requires at most 8 FS bit times (666 ns) [ 1.804663] hub 2-0:1.0: power on to power good time: 20ms [ 1.808782] hub 2-0:1.0: local power source is good [ 1.808864] usb usb1-port1: status 0501 change 0001 [ 1.817737] hub 2-0:1.0: trying to enable port power on non-switchable hub [ 1.826391] xhci_hcd 0000:00:14.0: new USB bus registered, assigned bus number 3 [ 1.834894] usb usb3: udev 1, busnum 3, minor = 256 [ 1.839285] usb usb3: New USB device found, idVendor=1d6b, idProduct=0003 [ 1.843655] usb usb3: New USB device strings: Mfr=3, Product=2, SerialNumber=1 [ 1.852190] usb usb3: Product: xHCI Host Controller [ 1.856551] usb usb3: Manufacturer: Linux 3.17.0-rc6-p xhci_hcd [ 1.860779] usb usb3: SerialNumber: 0000:00:14.0 [ 1.865157] hub 3-0:1.0: USB hub found [ 1.869285] hub 3-0:1.0: 1 port detected [ 1.873343] hub 3-0:1.0: standalone hub [ 1.877330] hub 3-0:1.0: no power switching (usb 1.0) [ 1.881318] hub 3-0:1.0: individual port over-current protection [ 1.885217] hub 3-0:1.0: TT requires at most 8 FS bit times (666 ns) [ 1.889062] hub 3-0:1.0: power on to power good time: 20ms [ 1.892931] hub 3-0:1.0: local power source is good [ 1.896895] hub 3-0:1.0: trying to enable port power on non-switchable hub [ 1.909106] hub 1-0:1.0: entry [ 1.922077] usb usb2-port2: status 0101 change 0001 [ 1.922104] usb usb2-port4: status 0101 change 0001 [ 2.021883] hub 2-0:1.0: entry [ 2.021886] hub 2-0:1.0: state 7 ports 6 chg 0014 evt 0000 [ 2.021900] usb usb2-port2: status 0101, change 0000, 12 Mb/s [ 2.057598] hub 1-0:1.0: state 7 ports 8 chg 0002 evt 0000 [ 2.057618] usb usb1-port1: status 0501, change 0000, 480 Mb/s [ 2.098844] hub 3-0:1.0: entry [ 2.103078] hub 3-0:1.0: state 7 ports 1 chg 0000 evt 0000 [ 2.107378] hub 3-0:1.0: exit [ 2.112024] hub 3-0:1.0: hub_suspend [ 2.141872] usb 2-2: new high-speed USB device number 2 using xhci_hcd [ 2.165884] usb 1-1: new high-speed USB device number 2 using ehci-pci [ 2.292660] usb 2-2: udev 2, busnum 2, minor = 129 [ 2.297388] usb 2-2: New USB device found, idVendor=05e3, idProduct=0608 [ 2.302132] usb 2-2: New USB device strings: Mfr=0, Product=1, SerialNumber=0 [ 2.306848] usb 2-2: Product: USB2.0 Hub [ 2.313803] hub 2-2:1.0: USB hub found [ 2.319849] hub 2-2:1.0: 4 ports detected [ 2.324262] hub 2-2:1.0: compound device; port removable status: FRRR [ 2.328802] hub 2-2:1.0: individual port power switching [ 2.333313] hub 2-2:1.0: individual port over-current protection [ 2.337703] hub 2-2:1.0: Single TT [ 2.341937] hub 2-2:1.0: TT requires at most 32 FS bit times (2664 ns) [ 2.346126] hub 2-2:1.0: Port indicators are supported [ 2.348073] usb 1-1: udev 2, busnum 1, minor = 1 [ 2.348076] usb 1-1: New USB device found, idVendor=8087, idProduct=07e6 [ 2.348078] usb 1-1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 2.362398] hub 2-2:1.0: power on to power good time: 100ms [ 2.368231] hub 1-1:1.0: USB hub found [ 2.374220] hub 2-2:1.0: local power source is good [ 2.375462] hub 1-1:1.0: 4 ports detected [ 2.375464] hub 1-1:1.0: standalone hub [ 2.375466] hub 1-1:1.0: individual port power switching [ 2.375468] hub 1-1:1.0: individual port over-current protection [ 2.375469] hub 1-1:1.0: Single TT [ 2.375471] hub 1-1:1.0: TT requires at most 8 FS bit times (666 ns) [ 2.375472] hub 1-1:1.0: power on to power good time: 0ms [ 2.377593] hub 1-1:1.0: local power source is good [ 2.377834] hub 1-1:1.0: enabling power on all ports [ 2.382109] hub 1-0:1.0: exit [ 2.414522] usb: failed to peer 2-2-port1 and usb3-port1 by location (2-2-port1:none) (usb3-port1:usb2-port1) [ 2.421240] usb 2-2-port1: failed to peer to usb3-port1 (-16) [ 2.424582] usb: port power management may be unreliable [ 2.428019] usb: failed to peer 2-2-port2 and usb3-port1 by location (2-2-port2:none) (usb3-port1:usb2-port1) [ 2.434676] usb 2-2-port2: failed to peer to usb3-port1 (-16) [ 2.438168] usb: failed to peer 2-2-port3 and usb3-port1 by location (2-2-port3:none) (usb3-port1:usb2-port1) [ 2.452348] usb 2-2-port3: failed to peer to usb3-port1 (-16) [ 2.456038] usb: failed to peer 2-2-port4 and usb3-port1 by location (2-2-port4:none) (usb3-port1:usb2-port1) [ 2.463595] usb 2-2-port4: failed to peer to usb3-port1 (-16) [ 2.471189] hub 2-2:1.0: enabling power on all ports [ 2.487005] hub 1-1:1.0: entry [ 2.487008] hub 1-1:1.0: state 7 ports 4 chg 0000 evt 0000 [ 2.487011] hub 1-1:1.0: exit [ 2.487017] hub 1-1:1.0: hub_suspend [ 2.489382] usb 1-1: usb auto-suspend, wakeup 1 [ 2.506143] hub 1-0:1.0: hub_suspend [ 2.527113] usb usb2-port4: status 0101, change 0000, 12 Mb/s [ 2.626715] usb 2-2-port1: status 0101 change 0001 [ 2.630965] usb 2-2-port2: status 0301 change 0001 [ 2.642400] usb 2-4: new high-speed USB device number 3 using xhci_hcd [ 2.734422] hub 2-2:1.0: entry [ 2.738919] hub 2-2:1.0: state 7 ports 4 chg 0006 evt 0000 [ 2.743724] usb 2-2-port1: status 0101, change 0000, 12 Mb/s [ 2.759608] usb 2-2-port1: indicator auto status 0 [ 2.786243] usb 2-4: udev 3, busnum 2, minor = 130 [ 2.790164] usb 2-4: New USB device found, idVendor=04f2, idProduct=b469 [ 2.794001] usb 2-4: New USB device strings: Mfr=1, Product=2, SerialNumber=0 [ 2.797774] usb 2-4: Product: HD WebCam [ 2.801517] usb 2-4: Manufacturer: Chicony Electronics Co.,Ltd. [ 2.807590] hub 2-0:1.0: exit [ 2.859427] usb 2-2.1: new full-speed USB device number 4 using xhci_hcd [ 2.952081] usb 2-2.1: udev 4, busnum 2, minor = 131 [ 2.956250] usb 2-2.1: New USB device found, idVendor=04ca, idProduct=300b [ 2.960509] usb 2-2.1: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 2.971332] usb 2-2-port2: status 0301, change 0000, 1.5 Mb/s [ 2.976113] usb 2-2-port2: indicator auto status 0 [ 3.055001] usb 2-2.2: new low-speed USB device number 5 using xhci_hcd [ 3.153553] usb 2-2.2: udev 5, busnum 2, minor = 132 [ 3.157847] usb 2-2.2: New USB device found, idVendor=04b3, idProduct=3108 [ 3.162409] usb 2-2.2: New USB device strings: Mfr=0, Product=0, SerialNumber=0 [ 3.171698] usb 2-2.2: ep 0x81 - rounding interval to 64 microframes, ep desc says 80 microframes [ 3.181748] hub 2-2:1.0: exit [ 3.186364] hub 2-2:1.0: entry [ 3.190831] hub 2-2:1.0: state 7 ports 4 chg 0000 evt 0004 [ 3.195632] hub 2-2:1.0: exit [ 3.865217] usbcore: registered new interface driver usbhid [ 3.865223] usbhid: USB HID core driver [ 3.896341] input: HD WebCam as /devices/pci0000:00/0000:00:14.0/usb2/2-4/2-4:1.0/input/input14 [ 3.897479] usbcore: registered new interface driver uvcvideo [ 3.897484] USB Video Class driver (1.1.1) [ 4.047481] input: HID 04b3:3108 as /devices/pci0000:00/0000:00:14.0/usb2/2-2/2-2.2/2-2.2:1.0/0003:04B3:3108.0001/input/input15 [ 4.047685] hid-generic 0003:04B3:3108.0001: input,hidraw0: USB HID v1.00 Mouse [HID 04b3:3108] on usb-0000:00:14.0-2.2/input0 [ 6.833668] usb 2-4: usb auto-suspend, wakeup 0 -- 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
