Messages in this thread | | | Date | Sat, 3 Mar 2001 16:07:13 +0100 (CET) | From | Geert Uytterhoeven <> | Subject | Re: IO issues vs. multiple busses |
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On Sat, 3 Mar 2001, Benjamin Herrenschmidt wrote: > With those two simple functions, we could at least > > - Have vgacon disable itself when there's no ISA memory (that can be ^^^^^^^^^^ > handled by > reserving the region and thus preventing request_region from working ^^^^^^^^^^^^^^ Do you mean request_mem_region()?
> too, well, > but that scheme would also simplify the various more/less hacked > macros used > on all non-x86 archs to access the VGA memory).
request_mem_region() for ISA memory is another problem point. The few drivers that use it seem to assume that the ISA memory base is 0. This won't work on non-PC machines, since ISA memory may be somewhere else in the address space, and more important, there already may be something different at address 0, which breaks request_mem_region(). On a PC the first 16 MB of RAM (with some holes at e.g. 0xa0000) overlap with ISA memory space, but not on other architectures.
For ioremap() we have a hack on PPC (PReP/CHRP) that adds isa_mem_base if the bus address to map falls in the first 16 MB area, but this cannot work for request_mem_region(). I do have my full memory map (RAM) marked in /proc/iomem.
So once again I vote for the introduction of isa_{request,release}_mem_region(), just like we already have isa_readb() and friends.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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