From owner-freebsd-current  Thu Jul 12  1:59:41 2001
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From: Søren Schmidt <sos@freebsd.dk>
Message-Id: <200107120859.f6C8xTl97891@freebsd.dk>
Subject: Re: Diagnosing a ata detection problem
In-Reply-To: <3B4CEB1C.37285B20@reason.levels.unisa.edu.au> "from Benjamin Close
 at Jul 12, 2001 09:41:08 am"
To: Benjamin Close <cisbjc@cs.unisa.edu.au>
Date: Thu, 12 Jul 2001 10:58:59 +0200 (CEST)
Cc: freebsd-current@FreeBSD.ORG
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It seems Benjamin Close wrote:
> Hi All,
> 	FreeBSD -current hasn't correctly detected the CDROM drive in my laptop
> for some time now. I've traced the problem down to the drive returning
> an invalid ATAPI_LSB_MAGIC and ATAPI_MSB_MAGIC which is checked at line
> 704 in dev/ata/ata-all.c
> 
> It returns d0 d0, which I believe is an overflow indication. My work
> around for this currently is comment out the if statement (as shown in
> the attached patch). Whilst, it's not elegant, it works. 

That patch will allow non-ATAPI devices to sneak past the probe,
which is not a good thing. If your drive doesn't return the
ATAPI magic's it is broken as this is a non dispensible part of
the spec. However it might be that your drive just has some
wierd timing requirements, so playing a bit with DELAY(N) in
the right places could do the trick.

> --- dev/ata/ata-all.c   Thu Jul 12 09:23:54 2001
> +++ dev/ata/ata-all.c.new       Thu Jul 12 09:22:04 2001
> @@ -701,7 +701,7 @@
>                 if (bootverbose)
>                     ata_printf(scp, ATA_SLAVE,
>                                "ATAPI probe %02x %02x\n", lsb, msb);
> -               if (lsb == ATAPI_MAGIC_LSB && msb == * ATAPI_MAGIC_MSB)
                                                       ^
					this is not in the official sources

> +               /*if (lsb == ATAPI_MAGIC_LSB && msb == *
> ATAPI_MAGIC_MSB)*/
>                      scp->devices |= ATA_ATAPI_SLAVE;
>              }
>          }

-Søren

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