Re: Logs being spammed with "Unable to enumerate USB device" - Kernel

This is a discussion on Re: Logs being spammed with "Unable to enumerate USB device" - Kernel ; Larry Finger wrote: > At times, my logs are filled with multiple copies of the following > message: > > hub 4-0:1.0: unable to enumerate USB device on port 5 > > The output of lsusb is as follows: > ...

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Thread: Re: Logs being spammed with "Unable to enumerate USB device"

  1. Re: Logs being spammed with "Unable to enumerate USB device"

    Larry Finger wrote:
    > At times, my logs are filled with multiple copies of the following
    > message:
    >
    > hub 4-0:1.0: unable to enumerate USB device on port 5
    >
    > The output of lsusb is as follows:
    >
    > Bus 003 Device 002: ID 04f2:b016 Chicony Electronics Co., Ltd
    > Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    > Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
    > Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
    > Bus 001 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
    >
    > The hubs are built into an HP dv2815nr laptop, and nothing is plugged in.
    >
    > I'm currently running v2.6.27-rc7 from the linux-2.6 git tree, but it
    > does not seem to be a regression. In checking my back logs, my first
    > such "storm" happened on July 25, with successive ones on September 8,
    > 9, 12 and 21.
    >
    > Is this an indication of hardware failure? What further info is
    > required? Any suggestions for debugging code to try to pinpoint the
    > problem?


    Is this just occurring during bootup? I think this is normal if the EHCI
    driver is loaded after UHCI or OHCI because it causes the device to be
    switched away from the other controller that's trying to enumerate it,
    at least momentarily.
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  2. Re: Logs being spammed with "Unable to enumerate USB device"

    Robert Han**** wrote:
    >
    > Is this just occurring during bootup? I think this is normal if the EHCI
    > driver is loaded after UHCI or OHCI because it causes the device to be
    > switched away from the other controller that's trying to enumerate it,
    > at least momentarily.


    It sometimes happens at bootup, but at other times I will get hundreds
    of them in a row in the logs. I have put in some debugging where the
    message is triggered, but have not seen any of the flood-type since.

    Larry


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  3. Re: Logs being spammed with "Unable to enumerate USB device"

    Larry Finger wrote:
    > Robert Han**** wrote:
    >> Is this just occurring during bootup? I think this is normal if the EHCI
    >> driver is loaded after UHCI or OHCI because it causes the device to be
    >> switched away from the other controller that's trying to enumerate it,
    >> at least momentarily.

    >
    > It sometimes happens at bootup, but at other times I will get hundreds
    > of them in a row in the logs. I have put in some debugging where the
    > message is triggered, but have not seen any of the flood-type since.


    I now have more information. The if statement that triggers the
    message is as follows:

    if (hub->hdev->parent ||
    !hcd->driver->port_handed_over ||
    !(hcd->driver->port_handed_over)(hcd, port1))

    For all the messages that I have captured, the first condition
    (hub->hdev->parent) is always true.

    For the isolated message that occurs at bootup, the second condition
    (!hcd->driver->port_handed_over) is true and the third is false.

    When the message storm occurs, the second condition is false, i.e.
    hcd->driver->port_handed_over is not zero, but
    !(hcd->driver->port_handed_over)(hcd, port1) is true.

    As before, I am willing to test any patches. As the message storm is
    rare, it will be difficult to show that a patch fixes the problem.

    Larry

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