diff options
| -rw-r--r-- | Documentation/admin-guide/pm/intel_idle.rst | 19 | ||||
| -rw-r--r-- | drivers/idle/intel_idle.c | 23 |
2 files changed, 38 insertions, 4 deletions
diff --git a/Documentation/admin-guide/pm/intel_idle.rst b/Documentation/admin-guide/pm/intel_idle.rst index 8998598746a4..89309e1b0e48 100644 --- a/Documentation/admin-guide/pm/intel_idle.rst +++ b/Documentation/admin-guide/pm/intel_idle.rst @@ -168,7 +168,7 @@ and ``idle=nomwait``. If any of them is present in the kernel command line, the ``MWAIT`` instruction is not allowed to be used, so the initialization of ``intel_idle`` will fail. -Apart from that there are three module parameters recognized by ``intel_idle`` +Apart from that there are four module parameters recognized by ``intel_idle`` itself that can be set via the kernel command line (they cannot be updated via sysfs, so that is the only way to change their values). @@ -195,6 +195,23 @@ driver ignore the system's ACPI tables entirely or use them for all of the recognized processor models, respectively (they both are unset by default and ``use_acpi`` has no effect if ``no_acpi`` is set). +The value of the ``states_off`` module parameter (0 by default) represents a +list of idle states to be disabled by default in the form of a bitmask. + +Namely, the positions of the bits that are set in the ``states_off`` value are +the indices of idle states to be disabled by default (as reflected by the names +of the corresponding idle state directories in ``sysfs``, :file:`state0`, +:file:`state1` ... :file:`state<i>` ..., where ``<i>`` is the index of the given +idle state; see :ref:`idle-states-representation` in :doc:`cpuidle`). + +For example, if ``states_off`` is equal to 3, the driver will disable idle +states 0 and 1 by default, and if it is equal to 8, idle state 3 will be +disabled by default and so on (bit positions beyond the maximum idle state index +are ignored). + +The idle states disabled this way can be enabled (on a per-CPU basis) from user +space via ``sysfs``. + .. _intel-idle-core-and-package-idle-states: diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 6fbd94f85fa5..d55606608ac8 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -63,6 +63,7 @@ static struct cpuidle_driver intel_idle_driver = { }; /* intel_idle.max_cstate=0 disables driver */ static int max_cstate = CPUIDLE_STATE_MAX - 1; +static unsigned int disabled_states_mask; static unsigned int mwait_substates; @@ -1234,6 +1235,9 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) if (cx->type > ACPI_STATE_C2) state->flags |= CPUIDLE_FLAG_TLB_FLUSHED; + if (disabled_states_mask & BIT(cstate)) + state->flags |= CPUIDLE_FLAG_OFF; + state->enter = intel_idle; state->enter_s2idle = intel_idle_s2idle; } @@ -1466,9 +1470,10 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv) /* Structure copy. */ drv->states[drv->state_count] = cpuidle_state_table[cstate]; - if ((icpu->use_acpi || force_use_acpi) && - intel_idle_off_by_default(mwait_hint) && - !(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE)) + if ((disabled_states_mask & BIT(drv->state_count)) || + ((icpu->use_acpi || force_use_acpi) && + intel_idle_off_by_default(mwait_hint) && + !(cpuidle_state_table[cstate].flags & CPUIDLE_FLAG_ALWAYS_ENABLE))) drv->states[drv->state_count].flags |= CPUIDLE_FLAG_OFF; drv->state_count++; @@ -1487,6 +1492,10 @@ static void __init intel_idle_init_cstates_icpu(struct cpuidle_driver *drv) static void __init intel_idle_cpuidle_driver_init(struct cpuidle_driver *drv) { cpuidle_poll_state_init(drv); + + if (disabled_states_mask & BIT(0)) + drv->states[0].flags |= CPUIDLE_FLAG_OFF; + drv->state_count = 1; if (icpu) @@ -1667,3 +1676,11 @@ device_initcall(intel_idle_init); * is the easiest way (currently) to continue doing that. */ module_param(max_cstate, int, 0444); +/* + * The positions of the bits that are set in this number are the indices of the + * idle states to be disabled by default (as reflected by the names of the + * corresponding idle state directories in sysfs, "state0", "state1" ... + * "state<i>" ..., where <i> is the index of the given state). + */ +module_param_named(states_off, disabled_states_mask, uint, 0444); +MODULE_PARM_DESC(states_off, "Mask of disabled idle states"); |