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| author | Len Brown <len.brown@intel.com> | 2014-02-14 06:50:34 +0100 |
|---|---|---|
| committer | Len Brown <len.brown@intel.com> | 2014-02-19 23:42:58 +0100 |
| commit | 24bfa950f114d5d770e482de73cf673a3b017f65 (patch) | |
| tree | 126199225a4045bc00db441c255ae4eb318efa2b /drivers/idle/intel_idle.c | |
| parent | ACPI idle: permit sparse C-state sub-state numbers (diff) | |
| download | linux-24bfa950f114d5d770e482de73cf673a3b017f65.tar.xz linux-24bfa950f114d5d770e482de73cf673a3b017f65.zip | |
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/intel_idle.c')
| -rw-r--r-- | drivers/idle/intel_idle.c | 9 |
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) && |