[linux-fbdev] Retrace

Benjamin Herrenschmidt bh40 at calva.net
Tue Feb 8 06:02:03 EST 2000

On Mon, Feb 7, 2000, Geert Uytterhoeven <geert at linux-m68k.org> wrote:

>And now the bad news: the address you have to mmap() depends on the machine
>type :-(

We need to find a solution for that one day or another. The iobase is not
only arch-dependant (PReP, PowerMac, CHRP...) but also machine dependant,
since it depends on the host bridge type.

Unfortunately, with weird host bridges like Apple Uni-N (that has 3
busses with 3 different io bases but the same bus number), it's almost
impossible to get it correct, or eventually by parsing /proc/device-tree.

That means that getting code that need to do io's from userland is a real
challenge. Even X is not completely correct in this regard. Ryuichi tried
to fix it at least for PowerMacs, but gave up for Uni-N based machines.

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

More information about the Linuxppc-dev mailing list