ACPI: cpufreq, processor: Detect old BIOS, not supporting CPU freq on a recent CPU. (910dfae2) · Commits · 戴 / test

On Intel CPUs it is rather common and a good hint that BIOSes which do provide _PPC func, but not the frequencies itself in _PSS function, are old and need to be updated for CPU freq support. Tell the user/vendor he has a BIOS/firmware problem. Make use of FW_BUG interface to give vendors and users the ability to automatically check with (or let linuxfirmwarekit do that): dmesg |grep "Firmware Bug" Signed-off-by:

Thomas Renninger <trenn@suse.de> Signed-off-by:

Andi Kleen <ak@linux.intel.com> Signed-off-by:

Len Brown <len.brown@intel.com>

drivers/acpi/processor_perflib.c

+15 −3

Original line number	Diff line number	Diff line
		@@ -38,6 +38,7 @@

		#include <asm/uaccess.h>
		#endif
		#include <asm/cpufeature.h>

		#include <acpi/acpi_bus.h>
		#include <acpi/processor.h>
		@@ -334,7 +335,6 @@ static int acpi_processor_get_performance_info(struct acpi_processor *pr)
		acpi_status status = AE_OK;
		acpi_handle handle = NULL;


		if (!pr \|\| !pr->performance \|\| !pr->handle)
		return -EINVAL;

		@@ -347,13 +347,25 @@ static int acpi_processor_get_performance_info(struct acpi_processor *pr)

		result = acpi_processor_get_performance_control(pr);
		if (result)
		return result;
		goto update_bios;

		result = acpi_processor_get_performance_states(pr);
		if (result)
		return result;
		goto update_bios;

		return 0;

		/*
		* Having _PPC but missing frequencies (_PSS, _PCT) is a very good hint that
		* the BIOS is older than the CPU and does not know its frequencies
		*/
		update_bios:
		if (ACPI_SUCCESS(acpi_get_handle(pr->handle, "_PPC", &handle))){
		if(boot_cpu_has(X86_FEATURE_EST))
		printk(KERN_WARNING FW_BUG "BIOS needs update for CPU "
		"frequency support\n");
		}
		return result;
		}

		int acpi_processor_notify_smm(struct module *calling_module)

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