ukbd attachment and root mount

Nate Eldredge neldredge at math.ucsd.edu
Wed Nov 12 04:18:37 PST 2008


On Wed, 12 Nov 2008, Andriy Gapon wrote:

> on 05/11/2008 17:24 Andriy Gapon said the following:
[...]
>> I have a legacy-free system (no PS/2 ports, only USB) and I wanted to
>> try a kernel without atkbd and psm (with ums, ukbd, kbdmux), but was
>> bitten hard when I made a mistake and kernel could not find/mount root
>> filesystem.
>>
>> So I stuck at mountroot prompt without a keyboard to enter anything.
>> This was repeatable about 10 times after which I resorted to live cd.
>>
>> Since then I put back atkbdc into my kernel. I guess BIOS or USB
>> hardware emulate AT or PS/2 keyboard, so the USB keyboard works before
>> the driver attaches. I guess I need such emulation e.g. for loader or
>> boot0 configuration. But I guess I don't have to have atkbd driver in
>> kernel.
>
> This turned out not to be a complete solution as it seems that there are
> some quirks about legacy USB here, sometimes keyboard stops working even
> at loader prompt (this is described in a different thread).
>
> ukbd attachment still puzzles me a lot.
> I look at some older dmesg, e.g. this 7.0-RELEASE one:
> http://www.mavetju.org/mail/view_message.php?list=freebsd-usb&id=2709973
> and see that ukbd attaches along with ums before mountroot.
>
> I look at newer dmesg and I see that ums attaches at about the same time
> as before but ukbd consistently attaches after mountroot.
> I wonder what might cause such behavior and how to fix it.
> I definitely would like to see ukbd attach before mountroot, I can debug
> this issue, but need some hints on where to start.

I haven't been following this thread, and I'm pretty sleepy right now, so 
sorry if this is irrelevant, but I had a somewhat similar problem that was 
fixed by adding

hint.atkbd.0.flags="0x1"

to /boot/device.hints .

-- 

Nate Eldredge
neldredge at math.ucsd.edu


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