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authorLen Brown <len.brown@intel.com>2014-02-14 00:50:34 -0500
committerLen Brown <len.brown@intel.com>2014-02-19 17:42:58 -0500
commit24bfa950f114d5d770e482de73cf673a3b017f65 (patch)
tree126199225a4045bc00db441c255ae4eb318efa2b /drivers/idle
parent2194324d8bbbad1b179c08b6095649b06abd62d5 (diff)
downloadkernel-24bfa950f114d5d770e482de73cf673a3b017f65.tar.gz
intel_idle: allow sparse sub-state numbering, for Bay Trail
Like acpi_idle, intel_idle compared sub-state numbers to the number of supported sub-states -- discarding sub-states numbers that were numbered >= the number of states. But some Bay Trail SOCs use sparse sub-state numbers, so we can't make such a comparison if we are going to access those states. So now we simply check that _some_ sub-states are supported for the given state, and assume that the sub-state number in our driver is valid. In practice, the driver is correct, and even if it were not, the hardware clips invalid sub-state requests to valid ones. No entries in the driver require this change, but Bay Trail will need it. Signed-off-by: Len Brown <len.brown@intel.com>
Diffstat (limited to 'drivers/idle')
-rw-r--r--drivers/idle/intel_idle.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 8e1939f564f4..057ffef37b42 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -584,7 +584,7 @@ static int __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, mwait_substate;
+ int num_substates, mwait_hint, mwait_cstate;
if (cpuidle_state_table[cstate].enter == NULL)
break;
@@ -597,14 +597,13 @@ static int __init intel_idle_cpuidle_driver_init(void)
mwait_hint = flg2MWAIT(cpuidle_state_table[cstate].flags);
mwait_cstate = MWAIT_HINT2CSTATE(mwait_hint);
- mwait_substate = MWAIT_HINT2SUBSTATE(mwait_hint);
- /* does the state exist in CPUID.MWAIT? */
+ /* number of sub-states for this state in CPUID.MWAIT */
num_substates = (mwait_substates >> ((mwait_cstate + 1) * 4))
& MWAIT_SUBSTATE_MASK;
- /* if sub-state in table is not enumerated by CPUID */
- if ((mwait_substate + 1) > num_substates)
+ /* if NO sub-states for this state in CPUID, skip it */
+ if (num_substates == 0)
continue;
if (((mwait_cstate + 1) > 2) &&