diff options
| -rw-r--r-- | drivers/idle/intel_idle.c | 49 |
1 files changed, 25 insertions, 24 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 75fd2a7b0842..47255d3cf51f 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -944,6 +944,22 @@ static void intel_idle_s2idle(struct cpuidle_device *dev, mwait_idle_with_hints(eax, ecx); } +static bool intel_idle_verify_cstate(unsigned int mwait_hint) +{ + unsigned int mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint) + 1; + unsigned int num_substates = (mwait_substates >> mwait_cstate * 4) & + MWAIT_SUBSTATE_MASK; + + /* Ignore the C-state if there are NO sub-states in CPUID for it. */ + if (num_substates == 0) + return false; + + if (mwait_cstate > 2 && !boot_cpu_has(X86_FEATURE_NONSTOP_TSC)) + mark_tsc_unstable("TSC halts in idle states deeper than C2"); + + return true; +} + static void __setup_broadcast_timer(bool on) { if (on) @@ -1332,10 +1348,10 @@ static void __init intel_idle_cpuidle_driver_init(void) drv->state_count = 1; for (cstate = 0; cstate < CPUIDLE_STATE_MAX; ++cstate) { - int num_substates, mwait_hint, mwait_cstate; + unsigned int mwait_hint; - if ((cpuidle_state_table[cstate].enter == NULL) && - (cpuidle_state_table[cstate].enter_s2idle == NULL)) + if (!cpuidle_state_table[cstate].enter && + !cpuidle_state_table[cstate].enter_s2idle) break; if (cstate + 1 > max_cstate) { @@ -1343,34 +1359,19 @@ static void __init intel_idle_cpuidle_driver_init(void) break; } - mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags); - mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint); - - /* number of sub-states for this state in CPUID.MWAIT */ - num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4)) - & MWAIT_SUBSTATE_MASK; - - /* if NO sub-states for this state in CPUID, skip it */ - if (num_substates == 0) - continue; - - /* if state marked as disabled, skip it */ + /* If marked as unusable, skip this state. */ if (cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_UNUSABLE) { pr_debug("state %s is disabled\n", cpuidle_state_table[cstate].name); continue; } + mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags); + if (!intel_idle_verify_cstate(mwait_hint)) + continue; - if (((mwait_cstate + 1) > 2) && - !boot_cpu_has(X86_FEATURE_NONSTOP_TSC)) - mark_tsc_unstable("TSC halts in idle" - " states deeper than C2"); - - drv->states[drv->state_count] = /* structure copy */ - cpuidle_state_table[cstate]; - - drv->state_count += 1; + /* Structure copy. */ + drv->states[drv->state_count++] = cpuidle_state_table[cstate]; } if (icpu->byt_auto_demotion_disable_flag) { |