From owner-freebsd-alpha  Fri Nov 17  9:30:41 2000
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Date: Fri, 17 Nov 2000 09:30:32 -0800 (PST)
From: John Baldwin <jhb@FreeBSD.org>
To: Andrew Gallatin <gallatin@cs.duke.edu>
Subject: Re: PC164 IDE only works (was: SMPng stability)
Cc: freebsd-alpha@FreeBSD.org,
	Christian Weisgerber <naddy@mips.inka.de>,
	Bernd Walter <ticso@cicely8.cicely.de>
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On 17-Nov-00 Andrew Gallatin wrote:
> 
> An interesting comment found in the linux kernel sources:
> 
>         /* In theory, the PC164 has the same interrupt hardware as
>            the other Cabriolet based systems.  However, something 
>            got screwed up late in the development cycle which broke
>            the interrupt masking hardware.  Repeat, it is not 
>            possible to mask and ack interrupts.  At all.
> 
>            In an attempt to work around this, while processing 
>            interrupts, we do not allow the IPL to drop below what
>            it is currently.  This prevents the possibility of
>            recursion.  
> 
>            ??? Another option might be to force all PCI devices
>            to use edge triggered rather than level triggered
>            interrupts.  That might be too invasive though.  */
> 
> 
> Drew

AUGH!!!!!!!!

This explains a lot. :(  Time to cook up an evil hack it looks like. :(

-- 

John Baldwin <jhb@FreeBSD.org> -- http://www.FreeBSD.org/~jhb/
PGP Key: http://www.baldwin.cx/~john/pgpkey.asc
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/


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