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authorLen Brown <len.brown@intel.com>2009-04-17 23:32:20 -0400
committerLen Brown <len.brown@intel.com>2009-04-17 23:32:20 -0400
commit96f15efcea94545987715f453a8c2b8ea592d000 (patch)
tree9dac5a4547357e311cc2be960b799a91ae3ee15d /drivers/acpi/sleep.c
parent0882e8dd3aad33eca41696d463bb896e6c8817eb (diff)
ACPI: Disable _GTS and _BFS support by default
Executing BIOS code paths not exercised by Windows tends to get Linux into trouble. However, if a system does benefit from _GTS or _BFS, acpi.gts=1 an acpi.bfs=1 are now available to enable them. http://bugzilla.kernel.org/show_bug.cgi?id=13041 Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/acpi/sleep.c')
-rw-r--r--drivers/acpi/sleep.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c
index 779e4e500df..9042875ac94 100644
--- a/drivers/acpi/sleep.c
+++ b/drivers/acpi/sleep.c
@@ -713,6 +713,32 @@ static void acpi_power_off(void)
acpi_enter_sleep_state(ACPI_STATE_S5);
}
+/*
+ * ACPI 2.0 created the optional _GTS and _BFS,
+ * but industry adoption has been neither rapid nor broad.
+ *
+ * Linux gets into trouble when it executes poorly validated
+ * paths through the BIOS, so disable _GTS and _BFS by default,
+ * but do speak up and offer the option to enable them.
+ */
+void __init acpi_gts_bfs_check(void)
+{
+ acpi_handle dummy;
+
+ if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__GTS, &dummy)))
+ {
+ printk(KERN_NOTICE PREFIX "BIOS offers _GTS\n");
+ printk(KERN_NOTICE PREFIX "If \"acpi.gts=1\" improves suspend, "
+ "please notify linux-acpi@vger.kernel.org\n");
+ }
+ if (ACPI_SUCCESS(acpi_get_handle(ACPI_ROOT_OBJECT, METHOD_NAME__BFS, &dummy)))
+ {
+ printk(KERN_NOTICE PREFIX "BIOS offers _BFS\n");
+ printk(KERN_NOTICE PREFIX "If \"acpi.bfs=1\" improves resume, "
+ "please notify linux-acpi@vger.kernel.org\n");
+ }
+}
+
int __init acpi_sleep_init(void)
{
acpi_status status;
@@ -771,5 +797,6 @@ int __init acpi_sleep_init(void)
* object can also be evaluated when the system enters S5.
*/
register_reboot_notifier(&tts_notifier);
+ acpi_gts_bfs_check();
return 0;
}