Re: port-xen/59350: PVHVM kernel cannot access cd unless vdev=hdc

["Manuel Bouyer via gnats" <gnats-admin%NetBSD.org@localhost>]

The following reply was made to PR port-xen/59350; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: port-xen-maintainer%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
        netbsd-bugs%netbsd.org@localhost
Subject: Re: port-xen/59350: PVHVM kernel cannot access cd unless vdev=hdc
Date: Thu, 24 Apr 2025 11:59:41 +0200

 On Thu, Apr 24, 2025 at 08:20:00AM +0000, netbsd%precedence.co.uk@localhost wrote:
 > [...[
 > If the CD device is hdb (or hdd) it will be mis-detected as a hard-disk and so the CD will not be usable:
 > 
 > wdc0 at isa0 port 0x1f0-0x1f7 irq 14
 > atabus0 at wdc0 channel 0
 > wd0 at atabus0 drive 0
 > wd0: 
 > wd0: drive supports 1-sector PIO transfers, chs addressing
 > wd0: 69632 KB, 1024 cyl, 8 head, 17 sec, 512 bytes/sect x 139264 sectors
 
 this is probably because in this case, the CD device appears as a slave
 IDE device, without master. In the ATA/ATAPI spec this is not a
 supported configuration, although with some hardware configuration it may
 work.
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --