kern/60526: Post-PAE stable SMP machine freezes

[Søren Schmidt]

The following reply was made to PR kern/60526; it has been noted by GNATS.

From: =?ISO-8859-1?Q?S=F8ren_Schmidt?= <sos at DeepCore.dk>
To: Doug White <dwhite at gumbysoft.com>
Cc: Eugene Grosbein <eugen at kuzbass.ru>, bug-followup at FreeBSD.ORG,
	stable at FreeBSD.ORG, sos at FreeBSD.ORG
Subject: Re: kern/60526: Post-PAE stable SMP machine freezes
Date: Thu, 18 Mar 2004 20:54:17 +0100

 Doug White wrote:
   >>According to
 >>http://freebsd.rambler.ru/bsdmail/freebsd-hackers_2003/msg03936.html
 >>the problem may be related to the <ServerWorks ROSB4 ATA33 controller>
 >>and ATA write cache (hw.ata.wc=1).
 > The problem is with DMA mode on these controllers, not write caching.
 > Write caching may help to get the data rate up fast enough to trigger the
 > bug, and turning it off slows things down.
 > 
 > I HIGHLY recommend using a DIFFERENT controller for disks. The ROSB4 is OK
 > for CDROMs and the like, but use a different controller for the system
 > drive.  Promise controllers work great. :)
 
 Cant disagree with the last sentence, however my only i386 SMP machine 
 has exactly the ROSB4 chip in it, and I use that for disks etc, newer 
 had a problem with it, but again this is an ASUS board and they 
 supposedly fixed the problem in HW (the *only* way to fix it btw).
 
 > ATA tagging is known to work with only a few disk models.  You should
 > enable ATA tags ONLY if you KNOW your drive supports it, and test
 > extensively to ensure stability.
 
 To be more exact, only a very few disks supports tags, in fact I only 
 know of IBM and a select few WDC disks that actually anounces support 
 for tags. The ATA driver (in -stable) only tries to enable tags if the 
 HW says it supports it and its a known to work drive. However the PAE 
 import has broken tags support so it doesn't work on any disks :(
 
 
 -- 
 -Søren