This e-mail is a follow-up as requested in this bug[1]. I will repost everything so far in this e-mail. Please CC me as I'm not subscribed to your list. Current head gives this when I plug a 'Mass Storage Device' into a 2.0 hub: [ 842.760400] hub 1-0:1.0: unable to enumerate USB device on port 3 [ 843.080058] usb 1-3: new high-speed USB device number 48 using ehci-pci [ 858.230072] usb 1-3: device descriptor read/64, error -110 [ 873.490070] usb 1-3: device descriptor read/64, error -110 Reverting the following commit makes it work again: commit 55bcdce8a8228223ec4d17d8ded8134ed265d2c5 Author: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Date: Fri Jan 25 16:52:45 2013 -0500 USB: EHCI: remove ASS/PSS polling timeout This patch (as1647) attempts to work around a problem that seems to affect some nVidia EHCI controllers. They sometimes take a very long time to turn off their async or periodic schedules. I don't know if this is a result of other problems, but in any case it seems wise not to depend on schedule enables or disables taking effect in any specific length of time. The patch removes the existing 20-ms timeout for enabling and disabling the schedules. The driver will now continue to poll the schedule state at 1-ms intervals until the controller finally decides to obey the most recent command issued by the driver. Just in case this hides a problem, a debugging message will be logged if the controller takes longer than 20 polls. I don't know if this will actually fix anything, but it can't hurt. Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Tested-by: Piergiorgio Sartor <piergiorgio.sartor@xxxxxxxx> CC: <stable@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c index 20dbdcb..f904071 100644 --- a/drivers/usb/host/ehci-timer.c +++ b/drivers/usb/host/ehci-timer.c @@ -113,14 +113,15 @@ static void ehci_poll_ASS(struct ehci_hcd *ehci) if (want != actual) { - /* Poll again later, but give up after about 20 ms */ - if (ehci->ASS_poll_count++ < 20) { - ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true); - return; - } - ehci_dbg(ehci, "Waited too long for the async schedule status(%x/%x), giving up\n", - want, actual); + /* Poll again later */ + ehci_enable_event(ehci, EHCI_HRTIMER_POLL_ASS, true); + ++ehci->ASS_poll_count; + return; } + + if (ehci->PSS_poll_count > 20) + ehci_dbg(ehci, "PSS poll count reached %d\n", + ehci->PSS_poll_count); ehci->PSS_poll_count = 0; /* The status is up-to-date; restart or stop the schedule as needed */ Please note, that I'm using the 'irqpoll' cmdline to improve system stability. What I forgot to mention in the bug was the chipset: 00:10.3 USB controller: VIA Technologies, Inc. USB 2.0 (rev 82) (prog-if 20 [EHCI]) Subsystem: Micro-Star International Co., Ltd. KT4AV motherboard Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx- Latency: 32, Cache Line Size: 32 bytes Interrupt: pin D routed to IRQ 21 Region 0: Memory at dffeff00 (32-bit, non-prefetchable) [size=256] Capabilities: [80] Power Management version 2 Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=375mA PME(D0+,D1+,D2+,D3hot+,D3cold+) Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME- Kernel driver in use: ehci-pci Yes, it's 10 years old, and no I'm not scrooge. We are waiting a while for computer prices to plummet mkay? [1]: https://bugzilla.kernel.org/show_bug.cgi?id=54031 -- 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