> Alan> thats really going to work well from user space. The moment you
> Alan> go digging into devices directly from user space you lose
> Alan> portability.
You loose portability because there is no writel() defined in 2.2 (since
2.13). Somehow that was not the case under 2.0. I think this needs to be
addressed. The simple way is to add writel() etc. to <asm/io.h>.
Besides, why i386/io.h does not know anything about writel() in non
__KERNEL__ , whereas alpha/io.h declares them as extern. That sure is
inconsitent.
On the other hand - WHY one loses portability doing IO memory access on
different architectures? Sure enough that PCI memory would be present on
any architecture that has that PCI plugged in, and registers would be the
same (though ordering might differ, and that is the responsibility of
writel() etc. to handle it.
>
> Hmmm, good point - I wonder how the XFree people solved this for the
> Alpha X servers.
Well, how does this fit with the point that user space IO memeory access
is bad? Sure enough X11 is all based on this "bad" concept.
On a side note, for hacking hardware I always missed MSDOS like debug in
Linux. As soon as I implemented tcl extension to that effect it is broken
in 2.0 to 2.2 transition.
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