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x86, setup: When probing memory with e801, use ax/bx as a pair

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When we use BIOS function e801 to probe memory, we should use ax/bx
(or cx/dx) as a pair, not mix and match.  This was a typo during the
translation from assembly code, and breaks at least one set of
machines in the field (which return cx = dx = 0).

Reported-and-tested-by: Chris Samuel <chris@csamuel.org>
Fix-proposed-by: Thomas Meyer <thomas@m3y3r.de>
Link: http://lkml.kernel.org/r/1303566747.12067.10.camel@localhost.localdomain
This commit is contained in:
H. Peter Anvin 2011-04-25 14:52:37 -07:00
parent 5dd12af05c
commit 39b68976ac
1 changed files with 1 additions and 1 deletions
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2
arch/x86/boot/memory.c
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@ -91,7 +91,7 @@ static int detect_memory_e801(void)
if (oreg.ax > 15*1024) {
return -1; /* Bogus! */
} else if (oreg.ax == 15*1024) {
boot_params.alt_mem_k = (oreg.dx << 6) + oreg.ax;
boot_params.alt_mem_k = (oreg.bx << 6) + oreg.ax;
} else {
/*
* This ignores memory above 16MB if we have a memory