Re: [BUG 2.6.31-rc1] HIGHMEM64G causes hang in PCI init on 32-bitx86

[Grant Grundler]

On Sat, Jun 27, 2009 at 11:45:24AM +0200, Mikael Pettersson wrote:
...
>   fff00000-fffffffe : pnp 00:09
> 100000000-1ffffffff : System RAM
> 200000000-ffffffffffffffff : RAM buffer
> 
> With 2.6.30 things look similar, except 2.6.30 does not show the
> last "200000000-ffffffffffffffff : RAM buffer" line.

BIOS e280 table didn't report that line.
I expect it's created by arch/x86/kernel/e820.c:
1398         /*
1399          * Try to bump up RAM regions to reasonable boundaries to
1400          * avoid stolen RAM:
1401          */
1402         for (i = 0; i < e820.nr_map; i++) {
1403                 struct e820entry *entry = &e820_saved.map[i];
1404                 resource_size_t start, end;
1405 
1406                 if (entry->type != E820_RAM)
1407                         continue;
1408                 start = entry->addr + entry->size;
1409                 end = round_up(start, ram_alignment(start));
1410                 if (start == end)
1411                         continue;
1412                 reserve_region_with_split(&iomem_resource, start,
1413                                                   end - 1, "RAM buffer");
1414         }

hth,
grant
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