Re: Problem with USB keyboard + ehci.mod

[Andrey Borzenkov]

В Mon, 28 Apr 2014 17:25:57 +0200
Richard Foltyn <address@hidden> пишет:

> Dear listers,
> 
> I have a USB hub/switch (ATEN US224) to share a USB keyboard / mouse
> between two computers.
> 
> On one of these computers, the keyboard in the grub2 menu works only
> if I pre-load ehci.mod (independent of whether "legacy USB support" is
> enabled in BIOS or not).
> 
> However, as soon as I load ehci.mod, the partitions present on the
> hard drive are no longer seen by grub2's ls

Yes; loading ehci explicitly disables native (BIOS) disk driver.

>                                            and I can no longer boot
> into Windows (Linux still works since it resides on LVM).
> I.e., BEFORE loading ehci, ls on the grub2 command line shows something like
> (hd0) (hd0,msdos1) (hd0,msdos2)  + some LVM volumes
> 
> AFTER I load ehci I see
> (usb0a) (usb0b) (usb0c) (usb0d) + some LVM volumes
> 

"some LVM volumes" is actually minor cosmetic bug here, but I'm not
sure how difficult it is to track all references.

I'm afraid this does not have easy solution. As I understand, native
driver is disabled because driver tells BIOS to relinquish USB control
and we do not know what is controlled - it could as well be hard disk
or other mass storage and we lose access to it (or worse crash system
when accessing it).

What you could try - try loading ahci driver (better via "nativedisk"
command if your version supports it - it will also load ehci among
others). Thus you will hopefully get native access (not via BIOS) to
the same disk.