Re: ATAPI CDROM probe failures
Erik Andersen (andersee@debian.org)
Sun, 5 Apr 1998 03:03:00 -0600
On Tue, Mar 31, 1998 at 11:41:58AM -0500, Glenn Burkhardt wrote:
> We recently received a couple of new computers equipped with Acer 24X CDROM
> drives, model 624A 217. To my dismay, they were not recognized by the initial
> probe at bootstrap with a 2.0.32 kernel. I obtained the 2.1.90 kernel source,
> build it, and tried again, but had the same result. The problem occurs with
> two different, identical model drives.
>
> Using the bootprompt 'hdc=cdrom' allowed me to mount and access the drive,
> with either kernel, with two different motherboards (PP200, PII-233, both
> from Acer).
>
> Other Acer 24x CDROM drives we obtained under the AcerOpen label work without
> any problems on these machines.
>
> I also tried booting Win95 and WinNT on these machines, and they both found
> the drive and were able access files without any problem.
>
> So, I had the following questions:
>
> 1. Is the firmware on the drives broken?
>
> 2. Could the Linux IDE probe routine be more forgiving, or in some way
> try harder to determine if a CDROM drive is attached?
>
> It seems clear from the ide-probe.c and ATAPI spec that these drives simply
> aren't responding to the 'IDENTIFY DRIVE' command 0xA1 (whose implemenation
> is mandatory, according to the ATAPI spec). But, on the other hand, the
> drives can be made to work otherwise. So what's standard operating procedure
> in the industry? Do manufactures occasionally disregard this part of the spec,
> simply because their firmware works with Win95 & WinNT?
>
> If my conclusions are correct, the other question, then is shouldn't the
> Linux driver follow the PC industry standard operating procedure of working
> with broken CDROM drive firmware?
>
> Pointers to previous discussions on these issues would be appreciated - the
> seach engine on linuxhq.com for the mailing list is broken...
>
>
[--------------snip----------------]
These drives sound remarkably like the Pioneer DR-A24 drives I
specifically mention in Documentation/cdrom/ide-cd. I wouldn't be
surprised if our friends at Acer have remarked Panasonic drives. Anyway,
for broken drives such as these the correct thing to do (per the
Documentation) is to "bypass the ATA probing which confuses these cdrom
drives, by adding `append="hdX=noprobe hdX=cdrom"' to your lilo.conf
file and runing lilo (again where X is the drive letter corresponding to
where your drive is installed.)"
-Erik
--
Erik B. Andersen Web: http://www.inconnect.com/~andersen/
email: andersee@debian.org
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