On 23 November 2015 at 23:52, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > On Sun, 22 Nov 2015, Daniel J Blueman wrote: > >> On 16 November 2015 at 23:22, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: >> > On Mon, 16 Nov 2015, Daniel J Blueman wrote: >> > >> >> Tuning USB suspend [1] in 4.3 on a Dell XPS 15 9553 (Skylake), I see a >> >> kworker thread spinning in rpm_suspend [2]. >> >> >> >> What is the most useful debug to get here beyond the immediate [3]? >> > >> > You can try doing: >> > >> > echo 'module usbcore =p' >/sys/kernel/debug/dynamic_debug/control >> >> kworker and ksoftirqd spinning occurs when I echo 'auto' to all the >> USB control entries. Using Alan's excellent tip, we see this being >> logged repeatedly at a high rate: >> [ 353.245180] usb usb1-port4: status 0107 change 0000 >> [ 353.245194] usb usb1-port12: status 0507 change 0000 >> [ 353.245202] hub 1-0:1.0: state 7 ports 16 chg 0000 evt 0000 >> [ 353.245203] hub 1-0:1.0: hub_suspend >> [ 353.245205] usb usb1: bus auto-suspend, wakeup 1 >> [ 353.245206] usb usb1: bus suspend fail, err -16 >> [ 353.245207] hub 1-0:1.0: hub_resume >> ... >> >> So, EBUSY. Both the webcam is not open, and the bluetooth interface >> [1] is rfkill'd; the situation occurs even if I unload all related >> modules. >> >> What further debug would be useful? >> >> Thanks! >> Daniel >> >> -- [1] >> >> Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub >> Bus 001 Device 002: ID 0a5c:6410 Broadcom Corp. >> Bus 001 Device 003: ID 1bcf:2b95 Sunplus Innovation Technology Inc. >> Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > Since bus 1 uses an xHCI controller, you should do: > > echo 'module xhci-hcd =p' >/sys/kernel/debug/dynamic_debug/control > > I'm reasonably sure this will end up printing "suspend failed > because a port is resuming", since that's the only place where > xhci_bus_suspend() fails with -EBUSY, but you should try it to confirm > this. I had to use: echo 'module xhci_hcd =p' >/sys/kernel/debug/dynamic_debug/control and indeed we see: [29172.246221] xhci_hcd 0000:00:14.0: get port status, actual port 11 status = 0xe63 [29172.246222] xhci_hcd 0000:00:14.0: Get port status returned 0x507 [29172.246224] xhci_hcd 0000:00:14.0: get port status, actual port 12 status = 0x2a0 [29172.246228] xhci_hcd 0000:00:14.0: get port status, actual port 13 status = 0x2a0 [29172.246228] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246231] xhci_hcd 0000:00:14.0: get port status, actual port 14 status = 0x2a0 [29172.246232] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246235] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246248] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246254] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246264] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246275] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246285] xhci_hcd 0000:00:14.0: Get port status returned 0x507 [29172.246294] xhci_hcd 0000:00:14.0: get port status, actual port 14 status = 0x2a0 [29172.246302] xhci_hcd 0000:00:14.0: suspend failed because a port is resuming [29172.246321] xhci_hcd 0000:00:14.0: Get port status returned 0x107 [29172.246332] xhci_hcd 0000:00:14.0: get port status, actual port 6 status = 0x2a0 [29172.246346] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246359] xhci_hcd 0000:00:14.0: get port status, actual port 13 status = 0x2a0 [29172.246364] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246366] xhci_hcd 0000:00:14.0: get port status, actual port 15 status = 0x2a0 [29172.246371] xhci_hcd 0000:00:14.0: suspend failed because a port is resuming [29172.246380] xhci_hcd 0000:00:14.0: Get port status returned 0x100 [29172.246382] xhci_hcd 0000:00:14.0: get port status, actual port 1 status = 0x2a0 [29172.246383] xhci_hcd 0000:00:14.0: Get port status returned 0x100 ... -- Daniel J Blueman -- 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
