Re: [PATCH v2] cpufreq: intel_pstate: skip the driver if ACPI has power mgmt option

[Adrian Huang <adrian.huang@hp.com>]

Will re-send it later. Sorry about that. 

於 三，2013-10-30 於 23:06 +0100，Rafael J. Wysocki 提到： 
> On Monday, October 28, 2013 05:22:10 PM Adrian Huang wrote:
> > This patch minimizes indentation levels and re-defines some local variables.
> 
> Care to add changelog describing what changes are made by the patch and why?
> 
> > Signed-off-by: Adrian Huang <adrian.huang@hp.com>
> > ---
> > Changes since v1:
> >  * Minimize indentation levels (Commented by Rafael)
> >  * Re-define some local variables (Commented by Rafael)
> >  * Return -ENODEV if platform FW has power management modes (Commented by Dirk)
> > 
> >  drivers/cpufreq/intel_pstate.c | 70 ++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 70 insertions(+)
> > 
> > diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
> > index eb3fdc7..8770d67 100644
> > --- a/drivers/cpufreq/intel_pstate.c
> > +++ b/drivers/cpufreq/intel_pstate.c
> > @@ -26,6 +26,8 @@
> >  #include <linux/fs.h>
> >  #include <linux/debugfs.h>
> >  #include <trace/events/power.h>
> > +#include <linux/acpi.h>
> > +#include <acpi/processor.h>
> >  
> >  #include <asm/div64.h>
> >  #include <asm/msr.h>
> > @@ -129,6 +131,18 @@ static struct perf_limits limits = {
> >  	.max_sysfs_pct = 100,
> >  };
> >  
> > +struct hw_vendor_info {
> > +	u16  valid;
> > +	char oem_id[ACPI_OEM_ID_SIZE];
> > +	char oem_table_id[ACPI_OEM_TABLE_ID_SIZE];
> > +};
> > +
> > +/* Hardware vendor-specific info that has its own power management modes */
> > +static struct hw_vendor_info vendor_info[] = {
> > +	{1, "HP    ", "ProLiant"},
> > +	{0, "", ""},
> > +};
> > +
> >  static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
> >  			int deadband, int integral) {
> >  	pid->setpoint = setpoint;
> > @@ -698,6 +712,55 @@ static int intel_pstate_msrs_not_valid(void)
> >  
> >  	return 0;
> >  }
> > +
> > +static bool intel_pstate_no_acpi_pss(void)
> > +{
> > +	int i;
> > +
> > +	for_each_possible_cpu(i) {
> > +		acpi_status status = AE_OK;
> > +		struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> > +		struct acpi_processor *pr = per_cpu(processors, i);
> > +		union acpi_object *pss = NULL;
> > +
> > +		if (!pr)
> > +			continue;
> > +
> > +		status = acpi_evaluate_object(pr->handle, "_PSS",
> > +					      NULL, &buffer);
> > +		if (ACPI_FAILURE(status))
> > +			continue;
> > +
> > +		pss = buffer.pointer;
> > +		if (pss && (pss->type == ACPI_TYPE_PACKAGE)) {
> > +			kfree(buffer.pointer);
> > +			return false;
> > +		}
> > +
> > +		kfree(buffer.pointer);
> > +	}
> > +
> > +	return true;
> > +}
> > +
> > +static bool intel_pstate_platform_pwr_mgmt_exists(void)
> > +{
> > +	struct acpi_table_header hdr;
> > +	struct hw_vendor_info *v_info;
> > +
> > +	if (ACPI_FAILURE(acpi_get_table_header(ACPI_SIG_FADT, 0, &hdr)))
> > +		return false;
> > +
> > +	for (v_info = vendor_info; v_info->valid; v_info++) {
> > +		if (!strncmp(hdr.oem_id, v_info->oem_id, ACPI_OEM_ID_SIZE)
> > +		    && !strncmp(hdr.oem_table_id, v_info->oem_table_id, ACPI_OEM_TABLE_ID_SIZE)
> > +		    && intel_pstate_no_acpi_pss())
> > +			return true;
> > +	}
> > +
> > +	return false;
> > +}
> > +
> >  static int __init intel_pstate_init(void)
> >  {
> >  	int cpu, rc = 0;
> > @@ -706,6 +769,13 @@ static int __init intel_pstate_init(void)
> >  	if (no_load)
> >  		return -ENODEV;
> >  
> > +	/*
> > +	 * The Intel pstate driver will be ignored if the platform
> > +	 * firmware has its own power management modes.
> > +	 */
> > +	if (!acpi_disabled && intel_pstate_platform_pwr_mgmt_exists())
> > +		return -ENODEV;
> > +
> >  	id = x86_match_cpu(intel_pstate_cpu_ids);
> >  	if (!id)
> >  		return -ENODEV;
> >