Subject: Re: Pyxis chip on a 500a.
To: None <port-alpha@netbsd.org>
From: Jeff Roberson <nomad@nop.aliensystems.com>
List: port-alpha
Date: 12/29/1999 10:30:36
I booted a freebsd, and a linux kernel on the machine last night.  Both,
to my surprise, worked.  Although freebsd doesn't support ide on the
machine, and I would rather not have the machine than use linux.  So this
leads me to wonder what netbsd does differently to cause the machine to
hang, and what work needs to be done to fix this.

Thanks,
Jeff

On 29 Dec 1999, Chris G. Demetriou wrote:

> Date: 29 Dec 1999 09:58:37 -0800
> From: Chris G. Demetriou <cgd@netbsd.org>
> To: Hal Murray <murray@pa.dec.com>
> Cc: Jeff Roberson <nomad@nop.aliensystems.com>, port-alpha@netbsd.org
> Subject: Re: Pyxis chip on a 500a.
> 
> I'm no miata wizard either, but the following might help folks:
> 
> Hal Murray <murray@pa.dec.com> writes:
> > The PCI-PCI bridge breaks transfers at page boundaries so that prevents 
> > the bug.
> 
> Actually, it breaks them up on "cache line boundaries" if i recall,
> and those will always be small (relative to the page size) powers of
> two, so it has the effect of making sure things are broken at page
> boundaries (as well as a lot of other places), at a performance cost.
> 
> 
> > I think only the 2 64 bit slots are not behind the bridge. 
> > 
> > I think the firmware knows that some cards don't provoke the problem.  
> > If it finds anything else in either of the two 64 bit slots, it complains.
> >
> > I think there is some command to disable that complaint.  I don't 
> > know if that's wise with your card.
> 
> Search for "set_pci_device_override" on mail-index.netbsd.org.
> That should probably help.  (Note that I don't think i've ever
> personally used a miata, so i can't say that i've done this myself.)
> 
> 
> 
> chris
> -- 
> Chris Demetriou - cgd@netbsd.org - http://www.netbsd.org/People/Pages/cgd.html
> Disclaimer: Not speaking for NetBSD, just expressing my own opinion.
>