Messages in this thread | | | From | "Tom Leete" <> | Subject | Re: holes for ISA boards... | Date | Fri, 11 Jun 1999 22:29:33 -0400 |
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-----Original Message----- From: Aaron J. Grier <aaron@frye.com>
>Summary: how do I make a memory "hole" for doing ISA I/O?
[...] >--- arch/i386/mm/init.c.orig Thu Jun 10 16:13:22 1999 >+++ arch/i386/mm/init.c Fri Jun 11 13:12:27 1999
[...] >+ if(virt_to_bus((void *)start_mem) < 0xC00000 && virt_to_bus((void *)start_mem) >= 0x1000000) {
This looks like "if(0)" to me. Might explain the oops, everything gets PG_reserved.
> clear_bit(PG_reserved, &mem_map[MAP_NR(start_mem)].flags); >- start_mem += PAGE_SIZE; >+ } else { >+ set_bit(PG_reserved, &mem_map[MAP_NR(start_mem)].flags); >+ } >+ start_mem += PAGE_SIZE;
I havn't absorbed the rest of the patch yet, so no further comment on the code.
I think this can be done if the Epson board is able to do ISA busmastering.
I've been looking at the bigphysarea patch to address a similar problem, but it is unsuitable for this. It does not accomodate memory holes, always placing its allocation as low as possible in memory.
I'll be very interested if you succeed at this. Rant of mine will be elsewhere in this thread.
Cheers Tom
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