On Fri, Apr 11, 2025 at 11:05:19 +0200, Edgar Fuß wrote:
> > You can create a custom kernel with a fixed set of attachments
> But how in this case?
> There’s some magic
> scsibus* at scsi*
> but no scsi at anything.
scsi is not device, it's an attribute. In Java terms, thinks classes
vs. interfaces. config(5) is a bit dense, but it documents all this.
conf/files has:
define scsi ...
device mpt: scsi
which is kinda "class mpt extends device implements scsi". As
config(5) says:
There is a special class of attribute, named interface attribute, which
represents a hook that allows a device to attach to (i.e., be a child of)
another device.
and here "scsi" is such an "interface attribute".
sys/dev/scsipi/files.scsipi has:
device scsibus ...
attach scsibus at scsi
that tries to attach scsibus to any device that "implements scsi"
interface attribute.
This is may be a bit unfortunate from the readability point of view,
as the name "scsi" just seemingly appears out of nowhere in the kernel
config file, b/c its definition is somwhere in sys/**/files* that you
don't see when you read/edit a kernel config. Think of this as a name
that comes from the "standard library", like printf, of FILE :) (sorry
for mixing Java and C metaphors).
-uwe
