Date: Wed, 2 Aug 2006 08:06:56 -0700 From: Jo Rhett <jrhett@svcolo.com> To: Bruce Evans <bde@zeta.org.au> Cc: njl@freebsd.org, freebsd-gnats-submit@freebsd.org, freebsd-i386@freebsd.org Subject: Re: i386/100831: sio ignores BIOS information about serial ports - bounty offered Message-ID: <20060802150656.GB47835@svcolo.com> In-Reply-To: <20060802234330.J1249@epsplex.bde.org> References: <200607252036.k6PKanFd072593@www.freebsd.org> <20060731191302.S1172@epsplex.bde.org> <6EFF87DF-280C-402C-8C2A-10F3144CF41F@svcolo.com> <20060802205230.N90692@delplex.bde.org> <20060802234330.J1249@epsplex.bde.org>
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On Thu, Aug 03, 2006 at 12:42:00AM +1000, Bruce Evans wrote:
> So only a limited workaround seems to be possible. There is currently
> no way to control ACPI's assignment of unit numbers, so device.hints
> must match that assignment. ACPI will use BIOS list order which
> associates unit 1 with port 0x3f8 in your preferred configuration.
> device.hints must match that to avoid later confusion but can't affect
> the unit numbers. You could keep COM1 == 0x3f8 in the boot loader and
> outside of FreeBSD but would have to swap unit numbers in device.hints
> and in all references to {tty,cua}d[0-1] in FreeBSD. Consoles actually
> cause the fewest problems here, since they can be refered to without
> using a unit number in most places and nothing except device.hints (or
> the driver) should need to be changed to make the references consistent.
Okay, I'm going to restate this in really simple terms. Tell me if I have
it right.
1. We can't/won't fix the sio0<->sio1 problem because fixing ACPI is hard
2. The sio units are thus going to swap when entering high-level sio mode
3. The workaround is to put flags 0x10 (or 0x90) on sio1
4. There should be no ill effect from doing this. Console will never break
and go to the wrong port.
#4 is crucial to us. Many of these machines are completely unavailable to
me for an emergency. This console is our "last chance access"
--
Jo Rhett
senior geek
SVcolo : Silicon Valley Colocation
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