From: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
de3ed81d746d ("[CPUFREQ] Change link order of x86 cpufreq modules")
changed cpufreq drivers link order so that powernow-k8 gets loaded first
due to earlier K8s having BIOS bugs.
However, now that acpi-cpufreq supports both AMD and Intel CPUs with HW
P-states, we want to load it first, so that cases where acpi-cpufreq and
powernow-k8 are both built-in and powernow-k8 initializing first, can be
addressed.
So, make sure that even if acpi-cpufreq gets loaded first, it errors out
on K8s and powernow-k8 can be loaded then successfully.
Signed-off-by: Matthew Garrett <mjg59@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20130118162347.GA31499@xxxxxxxxxxxxx
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
---
drivers/cpufreq/acpi-cpufreq.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c
index 0d048f6a2b23..31b06bbab54c 100644
--- a/drivers/cpufreq/acpi-cpufreq.c
+++ b/drivers/cpufreq/acpi-cpufreq.c
@@ -762,6 +762,12 @@ static int acpi_cpufreq_cpu_init(struct cpufreq_policy *policy)
switch (perf->control_register.space_id) {
case ACPI_ADR_SPACE_SYSTEM_IO:
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD &&
+ boot_cpu_data.x86 == 0xf) {
+ pr_debug("AMD K8 systems must use native drivers.\n");
+ result = -ENODEV;
+ goto err_unreg;
+ }
pr_debug("SYSTEM IO addr space\n");
data->cpu_feature = SYSTEM_IO_CAPABLE;
break;
--
1.8.1.rc3
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