Re: CVS commit: src/sys/dev/isa

[Matthias Drochner <M.Drochner%fz-juelich.de@localhost>]

dyoung%pobox.com@localhost said:
> How many pcdisplay at isa can there be one machine?

Iirc, this code is originating from alpha where you can have
multiple independant PCI/ISA/EISA hierarchies and thus
multiple pcdisplay/ega/vga devices.

> Can the two tags that pcdisplay_is_console() compared ever come from
> different spaces?

Yes, if there are independant ISA buses they are distinguished
by their tags.

> pcdisplay_is_console does not compare tag-handle tuples, it compares
> only tags.  Can it tell two instances of pcdisplay apart in that way?

I think this is just a simplification -- since you can have only one
pcdisplay per bus hierarchy you can have only one per tag.

> > MI code needs to be able to check for equality at least.
> I don't see the need.
This is done at other places as well, eg in com.c, which is used
by many (also embedded) architectures. (In this case, tag _and_
handle are compared -- one can have multiple com devices in any
of multiple address spaces.)
Not understanding some code is no excuse for breaking it.

best regards
Matthias



------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------
Forschungszentrum Juelich GmbH
52425 Juelich
Sitz der Gesellschaft: Juelich
Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498
Vorsitzende des Aufsichtsrats: MinDir'in Baerbel Brumme-Bothe
Geschaeftsfuehrung: Prof. Dr. Achim Bachem (Vorsitzender),
Dr. Ulrich Krafft (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt,
Prof. Dr. Sebastian M. Schmidt
------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------