[PATCH 1/2 v2] intel_pstate: skip this driver if Sun server has _PPC method

From: Ethan Zhao
Date: Mon Nov 24 2014 - 02:52:22 EST


Oracle Sun X86 servers have dynamic power capping capability that works via
ACPI _PPC method etc, so skip loading this driver if Sun server has ACPI _PPC
enabled.

Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>

v2: only match ORACLE oem id.
---
drivers/cpufreq/intel_pstate.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 27bb6d3..dacc15a 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -943,6 +943,21 @@ static bool intel_pstate_no_acpi_pss(void)
return true;
}

+static bool intel_pstate_has_acpi_ppc(void)
+{
+ int i;
+
+ for_each_possible_cpu(i) {
+ struct acpi_processor *pr = per_cpu(processors, i);
+
+ if (!pr)
+ continue;
+ if (acpi_has_method(pr->handle, "_PPC"))
+ return true;
+ }
+ return false;
+}
+
struct hw_vendor_info {
u16 valid;
char oem_id[ACPI_OEM_ID_SIZE];
@@ -952,6 +967,7 @@ struct hw_vendor_info {
/* Hardware vendor-specific info that has its own power management modes */
static struct hw_vendor_info vendor_info[] = {
{1, "HP ", "ProLiant"},
+ {1, "ORACLE", ""},
{0, "", ""},
};

@@ -970,11 +986,15 @@ static bool intel_pstate_platform_pwr_mgmt_exists(void)
intel_pstate_no_acpi_pss())
return true;
}
+ if (!strncmp(hdr.oem_id, vendor_info[1].oem_id, ACPI_OEM_ID_SIZE) &&
+ intel_pstate_has_acpi_ppc())
+ return true;

return false;
}
#else /* CONFIG_ACPI not enabled */
static inline bool intel_pstate_platform_pwr_mgmt_exists(void) { return false; }
+static inline bool intel_pstate_has_acpi_ppc(void) { return false; }
#endif /* CONFIG_ACPI */

static int __init intel_pstate_init(void)
--
1.8.3.1

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