Trying a Promise Ultra/66 on powerpc

Michel Lanners mlan at
Tue Aug 10 06:23:25 EST 1999

On   9 Aug, this message from Paul Mackerras echoed through cyberspace:
>> This fact was already catered for with the definition of outb/inb and
>> friends, which get an offset added to the port. Unfortunately, the
>> PowerMac IDE code undoes this and replaces it with a different
>> mechanism, which in essence removes the offset. Grrr..
> Not any more.  I took that stuff out a few weeks ago so that the
> CMD646 on the blue&white G3s could work.

Is that change in vger only? Submitted for 2.2.11?

> Basically the problem is that the IDE driver assumes that you access
> all IDE controllers via I/O ports.

Not a problem in itself, I guess: it's just that on the PPC, I/O ports
are not necessarily below 64k in processor-view..

> When you have a controller that
> has memory-mapped registers, there is a problem.  When you have a
> system where one IDE controller has I/O ports and another has memory-
> mapped registers, you have a bigger problem.  The current approach to
> solving this problem is to map the addresses of the memory-mapped
> registers into pseudo I/O port numbers (by subtracting _IO_BASE).  If
> there is a better way, somebody let me know. :-)

I'd vote for making I/O ports a memory addresss like any other, and
making sure drivers get this address right. See my other post for


Michel Lanners                 |  " Read Philosophy.  Study Art.
23, Rue Paul Henkes            |    Ask Questions.  Make Mistakes.
L-1710 Luxembourg              |
email   mlan at            |        |                     Learn Always. "

[[ This message was sent via the linuxppc-dev mailing list.  Replies are ]]
[[ not  forced  back  to the list, so be sure to Cc linuxppc-dev if your ]]
[[ reply is of general interest. Please check ]]
[[ and for useful information before posting.   ]]

More information about the Linuxppc-dev mailing list