Messages in this thread Patch in this message | | | Date | Sat, 6 Jan 2001 00:22:32 +0100 (MET) | From | Mikael Pettersson <> | Subject | 2.4.0 memory sizing broken on old x86 machines |
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Memory sizing for old machines whose BIOSen don't speak E820 got broken in 2.4.0-test13-pre4:
--- v2.4.0-test12/linux/arch/i386/kernel/setup.c Mon Dec 11 17:59:43 2000 +++ linux/arch/i386/kernel/setup.c Thu Dec 21 14:01:19 2000 @@ -518,7 +518,7 @@ e820.nr_map = 0; add_memory_region(0, LOWMEMSIZE(), E820_RAM); - add_memory_region(HIGH_MEMORY, mem_size << 10, E820_RAM); + add_memory_region(HIGH_MEMORY, (mem_size << 10) - HIGH_MEMORY, E820_RAM); } printk("BIOS-provided physical RAM map:\n"); print_memory_map(who); (This snipped is in setup_memory_region() where legacy (e801 or 88) memory size info is converted to e820-style.)
BIOS call 0x88 returns extended (above 1M) memory size not total, so the subtraction "- HIGH_MEMORY" is wrong. The effect is that the kernel believes the machine to have 1MB less RAM than it actually has -- not fun on an old 486 with limited RAM to start with :-(
I think this patch should be backed out pronto.
/Mikael - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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