install/44569: sysinst doesn't understand dkwedges

[Taylor R Campbell <campbell+netbsd%mumble.net@localhost>]

>Number:         44569
>Category:       install
>Synopsis:       sysinst doesn't understand dkwedges
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Feb 14 17:25:00 +0000 2011
>Originator:     Taylor R Campbell <campbell+netbsd%mumble.net@localhost>
>Release:        NetBSD 5.1_STABLE
>Organization:
>Environment:
System: NetBSD smalltalk.local 5.1_STABLE NetBSD 5.1_STABLE (RIADEBUG) #0: Tue 
Feb 1 20:28:45 UTC 2011 
root%smalltalk.local@localhost:/home/riastradh/netbsd/5/obj/sys/arch/i386/compile/RIADEBUG
 i386
Architecture: i386
Machine: i386
>Description:

        Sysinst doesn't understand dkwedges, so if the kernel
        autodetects dkwedges on a disk on which one wants to install
        NetBSD, sysinst will ignore the dkwedges, try to edit the
        underlying disk, and fail because the kernel won't allow that.

>How-To-Repeat:

        Boot the installer on a machine whose wd0 has a gpt.  Watch the
        kernel autodetect dkwedges.  Run sysinst.  Choose to install on
        wd0 because that is the only option sysinst gives.  Watch
        sysinst fail to open /dev/rwd0d during newfs because the kernel
        doesn't let you do that after it has already autodetected
        dkwedges.

>Fix:

        Yes, please!  Ideally, sysinst would be able to create gpts and
        maybe ponies too, but at least it should check for dkwedges and
        offer to install on the dkwedges rather than the disk in this
        case.  It's not enough just to disable dkwedge autodetection in
        the install kernel, and to let sysinst scribble over the gpt
        and use an mbr instead -- that would leave sysinst just as
        useless on the machines for which this matters, such as Intel
        Macs, which, as I understand it, insist on gpts.