Arch Linux

nbd

Member

Registered: 2014-08-04

Posts: 389

Warning about USB kernel modules during the boot

Hello,

I keep getting the following warning during the boot time (can be seen with journalctl -b):

Warning! ehci_hcd should always be loaded before uhci_hcd and ohci_hcd, not after

I have searched it and it looks like this message tells that USB driver modules are loaded in incorrect sequence and it can lead to unstable working of USB. Since I indeed have some strange issues with USB, can this message be an evidence of a problem with USB kernel modules in the Arch stock kernel?

My uname:

$ uname -a
Linux localhost 4.10.4-1-ARCH #1 SMP PREEMPT Sat Mar 18 19:39:18 CET 2017 x86_64 GNU/Linux

UPDATE:

There is even an ancient bug report at Arch Linux about this (reported as fixed):

https://bugs.archlinux.org/task/12009?p … &sort=desc

One of the comments there describes a possible problem with the incorrect order of loading modules:

ehci should be loaded before uhci/ohci, since a device capable of both USB1.1 and USB2.0 will get USB1.1 speeds if it is already inserted during boot time. Then ohci_hcd will "grab" the device as soon as this module is loaded.

Or is this actually not really a problem and a USB 2 device cannot be grabbed by the USB 1 module?

Last edited by nbd (2017-03-24 03:30:23)

---

bing different