[CPUFREQ] Longhaul - Option to disable ACPI C3 support
On some motherboards ACPI C3 is available, but it isn't
causing frequency transition on VIA Nehemiah. Longhaul
wasn't working at all earlier, but due to
scaling_cur_speed returning true CPU frequency now, it
looks like CPU is getting stuck at highest frequency
since 2.6.21. I didn't find a reason. Halt is causing
frequency transition.
Signed-off-by: Rafal Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
diff --git a/arch/i386/kernel/cpu/cpufreq/longhaul.c b/arch/i386/kernel/cpu/cpufreq/longhaul.c
index 8eca59d..ef8f0bc 100644
--- a/arch/i386/kernel/cpu/cpufreq/longhaul.c
+++ b/arch/i386/kernel/cpu/cpufreq/longhaul.c
@@ -75,6 +75,7 @@
/* Module parameters */
static int scale_voltage;
+static int disable_acpi_c3;
#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, "longhaul", msg)
@@ -844,6 +845,9 @@
if (cx->address > 0 && cx->latency <= 1000)
longhaul_flags |= USE_ACPI_C3;
}
+ /* Disable if it isn't working */
+ if (disable_acpi_c3)
+ longhaul_flags &= ~USE_ACPI_C3;
/* Check if northbridge is friendly */
if (enable_arbiter_disable())
longhaul_flags |= USE_NORTHBRIDGE;
@@ -952,6 +956,9 @@
kfree(longhaul_table);
}
+module_param (disable_acpi_c3, int, 0644);
+MODULE_PARM_DESC(disable_acpi_c3, "Don't use ACPI C3 support");
+
module_param (scale_voltage, int, 0644);
MODULE_PARM_DESC(scale_voltage, "Scale voltage of processor");