Re: Attachment order of scsibus*

[Valery Ushakov <uwe%stderr.spb.ru@localhost>]

On Fri, Apr 11, 2025 at 13:03:46 +0200, Edgar Fuß wrote:

> But can I write
>         scsibus0 at mpt0
>         scsibus1 at mpii0
>         scsibus* at scsi*

You can "wire down" any attachment.  Or rather, as config(5) says, you
can wildcard any attachment:

  instance at attachment [locator-specifications ...]
              Configures an instance of a device attaching at a specific
              location in the device tree.  All parameters can be
              wildcarded, with a ‘*’ for instance, and a ‘?’ for attachment
              and the locators.

E.g. sparc has a GENERIC_SCSI3 config:

	include "arch/sparc/conf/GENERIC"

	# Map the SCSI disk at targets 3120 to units 0123, a'la SunOS.
	sd0	at scsibus? target 3 lun ?	# first SCSI disk
	sd1	at scsibus? target 1 lun ?	# second SCSI disk
	sd2	at scsibus? target 2 lun ?	# third SCSI disk
	sd3	at scsibus? target 0 lun ?	# fourth SCSI disk

to emulate SunOS disk numbering by wiring down specific disk instances
to specific scsi targets.

If the wired down device cannot be attached its wildcard siblings will
not use that number.  E.g. note that you probably never see pckbc0
attached on an x86, b/c 0 is taken by the wired down "pckbc0 at isa?"
in the config and so you get "pckbc1 at acpi0 ..." etc on actual boot.

-uwe