Revert "cpufreq: intel_pstate: Use ACPI perf configuration"
authorRafael J. Wysocki <rafael.j.wysocki@intel.com>
Wed, 18 Nov 2015 23:20:42 +0000 (00:20 +0100)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Wed, 18 Nov 2015 23:20:42 +0000 (00:20 +0100)
Revert commit 37afb0003242 (cpufreq: intel_pstate: Use ACPI perf
configuration) that is reported to cause a regression to happen
on a system where invalid data are returned by the ACPI _PSS object.

Since that commit makes assumptions regarding the _PSS output
correctness that may turn out to be overly optimistic in general,
there is a concern that it may introduce regression on more
systems, so it's better to revert it now and we'll revisit the
underlying issue in the next cycle with a more robust solution.

Conflicts:
        drivers/cpufreq/intel_pstate.c

Fixes: 37afb0003242 (cpufreq: intel_pstate: Use ACPI perf configuration)
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/cpufreq/Kconfig.x86
drivers/cpufreq/intel_pstate.c

index adbd1de1cea55cbe6777d3a1c4dab546a6a68adf..c59bdcb83217071087cc0a90ef62e5cd01ce38d7 100644 (file)
@@ -5,7 +5,6 @@
 config X86_INTEL_PSTATE
        bool "Intel P state control"
        depends on X86
-       select ACPI_PROCESSOR if ACPI
        help
           This driver provides a P state for Intel core processors.
          The driver implements an internal governor and will become
index d444000ce148cb427ad66d310f535631b338f311..ef05944d8b165dd22c442fb0b4ba48d3c32a7df9 100644 (file)
 #include <asm/cpu_device_id.h>
 #include <asm/cpufeature.h>
 
-#if IS_ENABLED(CONFIG_ACPI)
-#include <acpi/processor.h>
-#endif
-
 #define BYT_RATIOS             0x66a
 #define BYT_VIDS               0x66b
 #define BYT_TURBO_RATIOS       0x66c
@@ -117,9 +113,6 @@ struct cpudata {
        u64     prev_mperf;
        u64     prev_tsc;
        struct sample sample;
-#if IS_ENABLED(CONFIG_ACPI)
-       struct acpi_processor_performance acpi_perf_data;
-#endif
 };
 
 static struct cpudata **all_cpu_data;
@@ -150,7 +143,6 @@ struct cpu_defaults {
 static struct pstate_adjust_policy pid_params;
 static struct pstate_funcs pstate_funcs;
 static int hwp_active;
-static int no_acpi_perf;
 
 struct perf_limits {
        int no_turbo;
@@ -197,153 +189,6 @@ static struct perf_limits *limits = &performance_limits;
 static struct perf_limits *limits = &powersave_limits;
 #endif
 
-#if IS_ENABLED(CONFIG_ACPI)
-/*
- * The max target pstate ratio is a 8 bit value in both PLATFORM_INFO MSR and
- * in TURBO_RATIO_LIMIT MSR, which pstate driver stores in max_pstate and
- * max_turbo_pstate fields. The PERF_CTL MSR contains 16 bit value for P state
- * ratio, out of it only high 8 bits are used. For example 0x1700 is setting
- * target ratio 0x17. The _PSS control value stores in a format which can be
- * directly written to PERF_CTL MSR. But in intel_pstate driver this shift
- * occurs during write to PERF_CTL (E.g. for cores core_set_pstate()).
- * This function converts the _PSS control value to intel pstate driver format
- * for comparison and assignment.
- */
-static int convert_to_native_pstate_format(struct cpudata *cpu, int index)
-{
-       return cpu->acpi_perf_data.states[index].control >> 8;
-}
-
-static int intel_pstate_init_perf_limits(struct cpufreq_policy *policy)
-{
-       struct cpudata *cpu;
-       int ret;
-       bool turbo_absent = false;
-       int max_pstate_index;
-       int min_pss_ctl, max_pss_ctl, turbo_pss_ctl;
-       int i;
-
-       cpu = all_cpu_data[policy->cpu];
-
-       pr_debug("intel_pstate: default limits 0x%x 0x%x 0x%x\n",
-                cpu->pstate.min_pstate, cpu->pstate.max_pstate,
-                cpu->pstate.turbo_pstate);
-
-       if (!cpu->acpi_perf_data.shared_cpu_map &&
-           zalloc_cpumask_var_node(&cpu->acpi_perf_data.shared_cpu_map,
-                                   GFP_KERNEL, cpu_to_node(policy->cpu))) {
-               return -ENOMEM;
-       }
-
-       ret = acpi_processor_register_performance(&cpu->acpi_perf_data,
-                                                 policy->cpu);
-       if (ret)
-               return ret;
-
-       /*
-        * Check if the control value in _PSS is for PERF_CTL MSR, which should
-        * guarantee that the states returned by it map to the states in our
-        * list directly.
-        */
-       if (cpu->acpi_perf_data.control_register.space_id !=
-                                               ACPI_ADR_SPACE_FIXED_HARDWARE)
-               return -EIO;
-
-       pr_debug("intel_pstate: CPU%u - ACPI _PSS perf data\n", policy->cpu);
-       for (i = 0; i < cpu->acpi_perf_data.state_count; i++)
-               pr_debug("     %cP%d: %u MHz, %u mW, 0x%x\n",
-                        (i == cpu->acpi_perf_data.state ? '*' : ' '), i,
-                        (u32) cpu->acpi_perf_data.states[i].core_frequency,
-                        (u32) cpu->acpi_perf_data.states[i].power,
-                        (u32) cpu->acpi_perf_data.states[i].control);
-
-       /*
-        * If there is only one entry _PSS, simply ignore _PSS and continue as
-        * usual without taking _PSS into account
-        */
-       if (cpu->acpi_perf_data.state_count < 2)
-               return 0;
-
-       turbo_pss_ctl = convert_to_native_pstate_format(cpu, 0);
-       min_pss_ctl = convert_to_native_pstate_format(cpu,
-                                       cpu->acpi_perf_data.state_count - 1);
-       /* Check if there is a turbo freq in _PSS */
-       if (turbo_pss_ctl <= cpu->pstate.max_pstate &&
-           turbo_pss_ctl > cpu->pstate.min_pstate) {
-               pr_debug("intel_pstate: no turbo range exists in _PSS\n");
-               limits->no_turbo = limits->turbo_disabled = 1;
-               cpu->pstate.turbo_pstate = cpu->pstate.max_pstate;
-               turbo_absent = true;
-       }
-
-       /* Check if the max non turbo p state < Intel P state max */
-       max_pstate_index = turbo_absent ? 0 : 1;
-       max_pss_ctl = convert_to_native_pstate_format(cpu, max_pstate_index);
-       if (max_pss_ctl < cpu->pstate.max_pstate &&
-           max_pss_ctl > cpu->pstate.min_pstate)
-               cpu->pstate.max_pstate = max_pss_ctl;
-
-       /* check If min perf > Intel P State min */
-       if (min_pss_ctl > cpu->pstate.min_pstate &&
-           min_pss_ctl < cpu->pstate.max_pstate) {
-               cpu->pstate.min_pstate = min_pss_ctl;
-               policy->cpuinfo.min_freq = min_pss_ctl * cpu->pstate.scaling;
-       }
-
-       if (turbo_absent)
-               policy->cpuinfo.max_freq = cpu->pstate.max_pstate *
-                                               cpu->pstate.scaling;
-       else {
-               policy->cpuinfo.max_freq = cpu->pstate.turbo_pstate *
-                                               cpu->pstate.scaling;
-               /*
-                * The _PSS table doesn't contain whole turbo frequency range.
-                * This just contains +1 MHZ above the max non turbo frequency,
-                * with control value corresponding to max turbo ratio. But
-                * when cpufreq set policy is called, it will call with this
-                * max frequency, which will cause a reduced performance as
-                * this driver uses real max turbo frequency as the max
-                * frequeny. So correct this frequency in _PSS table to
-                * correct max turbo frequency based on the turbo ratio.
-                * Also need to convert to MHz as _PSS freq is in MHz.
-                */
-               cpu->acpi_perf_data.states[0].core_frequency =
-                                               turbo_pss_ctl * 100;
-       }
-
-       pr_debug("intel_pstate: Updated limits using _PSS 0x%x 0x%x 0x%x\n",
-                cpu->pstate.min_pstate, cpu->pstate.max_pstate,
-                cpu->pstate.turbo_pstate);
-       pr_debug("intel_pstate: policy max_freq=%d Khz min_freq = %d KHz\n",
-                policy->cpuinfo.max_freq, policy->cpuinfo.min_freq);
-
-       return 0;
-}
-
-static int intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
-{
-       struct cpudata *cpu;
-
-       if (!no_acpi_perf)
-               return 0;
-
-       cpu = all_cpu_data[policy->cpu];
-       acpi_processor_unregister_performance(policy->cpu);
-       return 0;
-}
-
-#else
-static int intel_pstate_init_perf_limits(struct cpufreq_policy *policy)
-{
-       return 0;
-}
-
-static int intel_pstate_exit_perf_limits(struct cpufreq_policy *policy)
-{
-       return 0;
-}
-#endif
-
 static inline void pid_reset(struct _pid *pid, int setpoint, int busy,
                             int deadband, int integral) {
        pid->setpoint = setpoint;
@@ -1303,30 +1148,18 @@ static int intel_pstate_cpu_init(struct cpufreq_policy *policy)
        policy->cpuinfo.min_freq = cpu->pstate.min_pstate * cpu->pstate.scaling;
        policy->cpuinfo.max_freq =
                cpu->pstate.turbo_pstate * cpu->pstate.scaling;
-       if (!no_acpi_perf)
-               intel_pstate_init_perf_limits(policy);
-       /*
-        * If there is no acpi perf data or error, we ignore and use Intel P
-        * state calculated limits, So this is not fatal error.
-        */
        policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
        cpumask_set_cpu(policy->cpu, policy->cpus);
 
        return 0;
 }
 
-static int intel_pstate_cpu_exit(struct cpufreq_policy *policy)
-{
-       return intel_pstate_exit_perf_limits(policy);
-}
-
 static struct cpufreq_driver intel_pstate_driver = {
        .flags          = CPUFREQ_CONST_LOOPS,
        .verify         = intel_pstate_verify_policy,
        .setpolicy      = intel_pstate_set_policy,
        .get            = intel_pstate_get,
        .init           = intel_pstate_cpu_init,
-       .exit           = intel_pstate_cpu_exit,
        .stop_cpu       = intel_pstate_stop_cpu,
        .name           = "intel_pstate",
 };
@@ -1368,6 +1201,7 @@ static void copy_cpu_funcs(struct pstate_funcs *funcs)
 }
 
 #if IS_ENABLED(CONFIG_ACPI)
+#include <acpi/processor.h>
 
 static bool intel_pstate_no_acpi_pss(void)
 {
@@ -1563,9 +1397,6 @@ static int __init intel_pstate_setup(char *str)
                force_load = 1;
        if (!strcmp(str, "hwp_only"))
                hwp_only = 1;
-       if (!strcmp(str, "no_acpi"))
-               no_acpi_perf = 1;
-
        return 0;
 }
 early_param("intel_pstate", intel_pstate_setup);