Comment 7 for bug 296710

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Scott James Remnant (Canonical) (canonical-scott) wrote :

My opinion is that this is a kernel bug that the order matters at all.

ehci_hcd is the USB 2.0 HC driver.

ohci_hcd and uhci_hcd are the older USB 1.0 drivers.

Now imagine this scenario:

 * a laptop with only USB 1.0 Host Control Devices is booted

 * we'll only load ohci_hcd/uhci_hcd because those are all we need

 * hours/days/weeks later, the laptop owner plugs in a pccard that provides a USB 2.0 interface

 * we now load the ehci_hcd driver, and get that kernel warning

There's no way to guarantee module ordering, because there's no way to guarantee that the USB 2.0 hardware is even connected at the point we discover USB 1.0 hardware.

I'd therefore suggest there is no way to correct this in userspace.

The kernel should not be so stupid as to require a module ordering.

And arguable, those three drivers should be built in to the kernel anyway, then it can worry about it!