Messages in this thread | | | Date | Fri, 24 Oct 2008 09:57:37 -0400 (EDT) | From | Alan Stern <> | Subject | Re: [PATCH] usbcore: Limit number of 'unable to enumerate USB device' messages |
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On Thu, 23 Oct 2008, Larry Finger wrote:
> In my system, a number of messages that state "unable to enumerate USB device" > are logged. These are intermittent and likely due to some race condition > at bootup. > > Some of these happen when the EHCI driver is loaded after UHCI or OHCI, which > causes the device to be switched away from the other controller that's trying > to enumerate it, at least momentarily. This type of message is logged at most > once for each hub and occurs in about 70% of my reboots.
This is normal; it is caused by userspace loading the drivers in the wrong order. ehci-hcd is supposed to be loaded before uhci-hcd or ohci-hcd, not after. There's no point trying to change the kernel to avoid it.
> A more insidious form of the message occurs hundreds of times in about 10% of > reboots. They continue until the system is rebooted. This patch limits the > number of these messages to 20. Once the actual cause of this message is > located, this patch can be reverted.
I would prefer to attack this problem directly rather than wallpaper over it. Can you provide more information? For example, a dmesg log with CONFIG_USB_DEBUG and CONFIG_PRINTK_TIME enabled would help. It might also help to know what the devices which can't be enumerated actually are.
Alan Stern
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