By default, the old P-state driver (acpi-freq) is used. Adding
intel_pstate to the Xen booting param list to enable the
use of intel_pstate. However, if intel_pstate is enabled on a
machine which does not support the driver (e.g. Nehalem), the
old P-state driver will be loaded due to the failure loading of
intel_pstate.
Also, adding the intel_pstate booting parameter to
xen-command-line.markdown.
v4 changes:
1) moved the definition of load_intel_pstate right ahead of
intel_pstate_init();
2) merged the previous patch,adding the booting param to
xen.command-line.markdown, into this one.
Signed-off-by: Wei Wang wei.w.w...@intel.com
---
docs/misc/xen-command-line.markdown | 7 +++
xen/arch/x86/acpi/cpufreq/cpufreq.c | 9 ++---
xen/arch/x86/acpi/cpufreq/intel_pstate.c | 6 ++
3 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/docs/misc/xen-command-line.markdown
b/docs/misc/xen-command-line.markdown
index 4889e27..249bf65 100644
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -830,6 +830,13 @@ debug hypervisor only).
### idle\_latency\_factor
`= integer`
+### intel\_pstate
+ `= boolean`
+
+ Default: `false`
+
+Enable the loading of the intel pstate driver.
+
### ioapic\_ack
`= old | new`
diff --git a/xen/arch/x86/acpi/cpufreq/cpufreq.c
b/xen/arch/x86/acpi/cpufreq/cpufreq.c
index 643c405..e737437 100644
--- a/xen/arch/x86/acpi/cpufreq/cpufreq.c
+++ b/xen/arch/x86/acpi/cpufreq/cpufreq.c
@@ -41,6 +41,7 @@
#include asm/processor.h
#include asm/percpu.h
#include asm/cpufeature.h
+#include asm/cpufreq.h
#include acpi/acpi.h
#include acpi/cpufreq/cpufreq.h
@@ -648,9 +649,11 @@ static int __init cpufreq_driver_init(void)
int ret = 0;
if ((cpufreq_controller == FREQCTL_xen)
-(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL))
-ret = cpufreq_register_driver(acpi_cpufreq_driver);
-else if ((cpufreq_controller == FREQCTL_xen)
+(boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)) {
+ret = intel_pstate_init();
+if (ret)
+ret = cpufreq_register_driver(acpi_cpufreq_driver);
+} else if ((cpufreq_controller == FREQCTL_xen)
(boot_cpu_data.x86_vendor == X86_VENDOR_AMD))
ret = powernow_register_driver();
diff --git a/xen/arch/x86/acpi/cpufreq/intel_pstate.c
b/xen/arch/x86/acpi/cpufreq/intel_pstate.c
index 19c74cc..5e03625 100644
--- a/xen/arch/x86/acpi/cpufreq/intel_pstate.c
+++ b/xen/arch/x86/acpi/cpufreq/intel_pstate.c
@@ -831,12 +831,18 @@ static void __init copy_cpu_funcs(struct pstate_funcs
*funcs)
pstate_funcs.get_vid = funcs-get_vid;
}
+static bool_t __initdata load_intel_pstate;
+boolean_param(intel_pstate, load_intel_pstate);
+
int __init intel_pstate_init(void)
{
int cpu, rc = 0;
const struct x86_cpu_id *id;
struct cpu_defaults *cpu_info;
+ if (!load_intel_pstate)
+ return -ENODEV;
+
id = x86_match_cpu(intel_pstate_cpu_ids);
if (!id)
return -ENODEV;
--
1.9.1
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