intel_pstate: remove setting P state to MAX on init
authorDirk Brandewie <dirk.j.brandewie@intel.com>
Thu, 8 May 2014 19:57:24 +0000 (12:57 -0700)
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>
Tue, 13 May 2014 15:39:13 +0000 (17:39 +0200)
Setting the P state of the core to max at init time is a hold over
from early implementation of intel_pstate where intel_pstate disabled
cpufreq and loaded VERY early in the boot sequence.  This was to
ensure that intel_pstate did not affect boot time. This in not needed
now that intel_pstate is a cpufreq driver.

Removing this covers the case where a CPU has gone through a manual
CPU offline/online cycle and the P state is set to MAX on init and the
CPU immediately goes idle.  Due to HW coordination the P state request
on the idle CPU will drag all cores to MAX P state until the load is
reevaluated when to core goes non-idle.

Reported-by: Patrick Marlier <patrick.marlier@gmail.com>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Cc: 3.14+ <stable@vger.kernel.org> # 3.14+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
drivers/cpufreq/intel_pstate.c

index 39c4f85208487097ed1df131afd2db9c858fe1f7..eab8ccfe6bebed652b8fec4849a5fc9fb67d82f3 100644 (file)
@@ -554,12 +554,7 @@ static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
 
        if (pstate_funcs.get_vid)
                pstate_funcs.get_vid(cpu);
-
-       /*
-        * goto max pstate so we don't slow up boot if we are built-in if we are
-        * a module we will take care of it during normal operation
-        */
-       intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
+       intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
 }
 
 static inline void intel_pstate_calc_busy(struct cpudata *cpu,
@@ -704,11 +699,6 @@ static int intel_pstate_init_cpu(unsigned int cpunum)
        cpu = all_cpu_data[cpunum];
 
        intel_pstate_get_cpu_pstates(cpu);
-       if (!cpu->pstate.current_pstate) {
-               all_cpu_data[cpunum] = NULL;
-               kfree(cpu);
-               return -ENODATA;
-       }
 
        cpu->cpu = cpunum;
 
@@ -719,7 +709,6 @@ static int intel_pstate_init_cpu(unsigned int cpunum)
        cpu->timer.expires = jiffies + HZ/100;
        intel_pstate_busy_pid_reset(cpu);
        intel_pstate_sample(cpu);
-       intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate);
 
        add_timer_on(&cpu->timer, cpunum);