Re: Issue with /usr/src/sys/arch/i386/stand/lib/gatea20.c

["Perry E. Metzger" <perry%piermont.com@localhost>]

David Laight <david%l8s.co.uk@localhost> writes:
>> No I have not but I will now. Thanks Jukka.
>> But if it works, why the heck isn't it commited?
>
> Because the code that is there was added for a reason - probably to
> make some other motherboard work properly.

In fact, there are a very large number of boards that require (or used
to require) the Gate A20 hack.

> Unless and until you understand the full ramifications of such a
> change, you are likely to break the boot code on some other
> platform.
>
> The A20 gate is a horrid hack, and it is probably difficult to find any
> reasonable amount of documentation about it.

What we might do is explicitly check whether or not the device is
there before hitting gate A20, but on the other hand I don't know if
there is an easy way to do that.

-- 
Perry E. Metzger                perry%piermont.com@localhost