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authorLinus Torvalds <torvalds@linux-foundation.org>2009-03-28 13:40:20 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2009-03-28 13:48:38 -0700
commit7c730ccdc1188b97f5c8cb690906242c7ed75c22 (patch)
tree17ccd927e70dadaf59104c53cce892474eb539b2 /arch/x86/boot/a20.c
parent8d735b4148d46446e64d72b22ef0344ee8dc02fa (diff)
parent82268da1b130f763d22d04f7d016bbf6fc8815c2 (diff)
Merge branch 'percpu-cpumask-x86-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'percpu-cpumask-x86-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (682 commits) percpu: fix spurious alignment WARN in legacy SMP percpu allocator percpu: generalize embedding first chunk setup helper percpu: more flexibility for @dyn_size of pcpu_setup_first_chunk() percpu: make x86 addr <-> pcpu ptr conversion macros generic linker script: define __per_cpu_load on all SMP capable archs x86: UV: remove uv_flush_tlb_others() WARN_ON percpu: finer grained locking to break deadlock and allow atomic free percpu: move fully free chunk reclamation into a work percpu: move chunk area map extension out of area allocation percpu: replace pcpu_realloc() with pcpu_mem_alloc() and pcpu_mem_free() x86, percpu: setup reserved percpu area for x86_64 percpu, module: implement reserved allocation and use it for module percpu variables percpu: add an indirection ptr for chunk page map access x86: make embedding percpu allocator return excessive free space percpu: use negative for auto for pcpu_setup_first_chunk() arguments percpu: improve first chunk initial area map handling percpu: cosmetic renames in pcpu_setup_first_chunk() percpu: clean up percpu constants x86: un-__init fill_pud/pmd/pte x86: remove vestigial fix_ioremap prototypes ... Manually merge conflicts in arch/ia64/kernel/irq_ia64.c
Diffstat (limited to 'arch/x86/boot/a20.c')
-rw-r--r--arch/x86/boot/a20.c79
1 files changed, 40 insertions, 39 deletions
diff --git a/arch/x86/boot/a20.c b/arch/x86/boot/a20.c
index 4063d630deff..7c19ce8c2442 100644
--- a/arch/x86/boot/a20.c
+++ b/arch/x86/boot/a20.c
@@ -2,6 +2,7 @@
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007-2008 rPath, Inc. - All Rights Reserved
+ * Copyright 2009 Intel Corporation
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
@@ -15,16 +16,23 @@
#include "boot.h"
#define MAX_8042_LOOPS 100000
+#define MAX_8042_FF 32
static int empty_8042(void)
{
u8 status;
int loops = MAX_8042_LOOPS;
+ int ffs = MAX_8042_FF;
while (loops--) {
io_delay();
status = inb(0x64);
+ if (status == 0xff) {
+ /* FF is a plausible, but very unlikely status */
+ if (!--ffs)
+ return -1; /* Assume no KBC present */
+ }
if (status & 1) {
/* Read and discard input data */
io_delay();
@@ -118,44 +126,37 @@ static void enable_a20_fast(void)
int enable_a20(void)
{
-#if defined(CONFIG_X86_ELAN)
- /* Elan croaks if we try to touch the KBC */
- enable_a20_fast();
- while (!a20_test_long())
- ;
- return 0;
-#elif defined(CONFIG_X86_VOYAGER)
- /* On Voyager, a20_test() is unsafe? */
- enable_a20_kbc();
- return 0;
-#else
int loops = A20_ENABLE_LOOPS;
- while (loops--) {
- /* First, check to see if A20 is already enabled
- (legacy free, etc.) */
- if (a20_test_short())
- return 0;
-
- /* Next, try the BIOS (INT 0x15, AX=0x2401) */
- enable_a20_bios();
- if (a20_test_short())
- return 0;
-
- /* Try enabling A20 through the keyboard controller */
- empty_8042();
- if (a20_test_short())
- return 0; /* BIOS worked, but with delayed reaction */
-
- enable_a20_kbc();
- if (a20_test_long())
- return 0;
-
- /* Finally, try enabling the "fast A20 gate" */
- enable_a20_fast();
- if (a20_test_long())
- return 0;
- }
-
- return -1;
-#endif
+ int kbc_err;
+
+ while (loops--) {
+ /* First, check to see if A20 is already enabled
+ (legacy free, etc.) */
+ if (a20_test_short())
+ return 0;
+
+ /* Next, try the BIOS (INT 0x15, AX=0x2401) */
+ enable_a20_bios();
+ if (a20_test_short())
+ return 0;
+
+ /* Try enabling A20 through the keyboard controller */
+ kbc_err = empty_8042();
+
+ if (a20_test_short())
+ return 0; /* BIOS worked, but with delayed reaction */
+
+ if (!kbc_err) {
+ enable_a20_kbc();
+ if (a20_test_long())
+ return 0;
+ }
+
+ /* Finally, try enabling the "fast A20 gate" */
+ enable_a20_fast();
+ if (a20_test_long())
+ return 0;
+ }
+
+ return -1;
}