Subject: Re: have scsibus sleep only one time
To: Greywolf <>
From: Manuel Bouyer <>
List: tech-kern
Date: 03/10/2003 02:45:52
On Mon, Mar 10, 2003 at 01:33:46AM +0000, Greywolf wrote:
> Thus spake Manuel Bouyer ("MB> ") sometime Yesterday...
> MB> Hi,
> MB> would anyone object to the attached change ?
> MB> It makes all the attached scsibusses sleep "in parallel" instead of
> MB> sequencially, which is a real win for machines with several SCSI busses.
> MB> On my DS20, which has 8 scsi busses, this saves 14 seconds on boot.
> I've been wondering about this for years now.  Why we couldn't issue bus
> resets in parallel on all the buses and then they'd all be ready to scan,
> I'm not sure.

They are issued in parallel (in fact, they are issued when the HBA driver

> Someone must have a reason we need to wait sequentially...?

I think this is mostly historical, with the old code is was not that simple
to wait once for all busses to probe now (but we stil want to wait if a
hot-plug bus comes later).

Manuel Bouyer <>
     NetBSD: 24 ans d'experience feront toujours la difference