# "Unable to enumerate USB device"

## Akaihiryuu

Ok, sometime in the past 6 months, USB keyboards stopped working on my Gentoo server.  Other USB devices (like flash drives) work fine:

```
Jan 28 13:07:02 triforce kernel: usb 1-6: new high speed USB device number 7 using ehci_hcd

Jan 28 13:07:02 triforce kernel: SCSI subsystem initialized

Jan 28 13:07:02 triforce kernel: Initializing USB Mass Storage driver...
```

But keyboards do not:

```
Jan 28 13:09:03 triforce kernel: usb 4-2: new low speed USB device number 6 using uhci_hcd

Jan 28 13:09:18 triforce kernel: hub 4-0:1.0: unable to enumerate USB device on port 2
```

I'm out of ideas.  This is a VIA chipset that has UHCI and EHCI.Last edited by Akaihiryuu on Thu Feb 02, 2012 11:17 pm; edited 1 time in total

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## eccerr0r

You mention "usb keyboards" indicating more than one fail?

The error you got usually indicates bad USB hardware.  If you have more than one that doesn't work yet USB-storage works on that same port, makes no sense...

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## energyman76b

and you have of course hid support turned on under usb support?

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## Logicien

Hello,

I got that message with a USB cellular modem that include a cdrom image when I use it with a usb cacle. The BIOS do not recognise the cdrom and Linux tell me "Unable to enumerate USB device" at early boot. But when I log in, it work. If I plug it directly in the USB connector, the BIOS see it and I do not see this message. When I use the USB cellular modem with a USB hub, BIOS see cdrom and no error message.

So, I think it is because I bought the USB cable et a one dollar (1$) store and it is cheap. I did not check with an other cable. An other device that can give the message "Unable to enumerate USB device" from Linux at boot time is my USB mouse. It work to in session.

It look like as if Linux need to drive some devices itself to be able to enumarate them. It can not do it from a BIOS call it the BIOS can not enumerate those devices itself. Probably put the USB support in hard in the kernel would resolv the problem.

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## energyman76b

do yourself a favour and do not compile in usb support. Keep ehci, uhci, ohci, xhci modular. Sometimes some device will fuck your bus up. No problem, rmmod && modprobe and everything works again. But compiled in....

Failure to 'enumerate' is either hardware or driver.

Those umts sticks with their fake-cdrom are a different problem, solved by the right udev rule.

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## Logicien

So, why sometimes the enumarate message show and somtimes not depending on material setup, without changing Udev rules?

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## energyman76b

 *Logicien wrote:*   

> So, why sometimes the enumarate message show and somtimes not depending on material setup, without changing Udev rules?

 

read my post again?

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## Akaihiryuu

Sorry, I missed the replies to this because I forgot to check the notification box.  But to answer the question, NO USB keyboard will work on that machine.  I have tried 3 of them (all of which used to work), all give this error.  This started after the OpenRC migration.

I have tested all 3 keyboards...all work fine on my gaming computer (which has Win7...they also work fine in the BIOS though).  Any other USB device works fine on the Linux server, just not a keyboard.  I do have USB HID support (it's a module, and so are my other USB options).

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