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| author | Chen Yu <yu.c.chen@intel.com> | 2020-10-24 18:29:53 +0200 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2020-10-27 19:03:53 +0100 |
| commit | 4e0ba5577dba686f96c1c10ef4166380667fdec7 (patch) | |
| tree | f7234fa8ab802e6d76c885b486857046af8523a3 /drivers/idle | |
| parent | Linux 5.10-rc1 (diff) | |
| download | linux-4e0ba5577dba686f96c1c10ef4166380667fdec7.tar.xz linux-4e0ba5577dba686f96c1c10ef4166380667fdec7.zip | |
intel_idle: Fix max_cstate for processor models without C-state tables
Currently intel_idle driver gets the c-state information from ACPI
_CST if the processor model is not recognized by it. However the
c-state in _CST starts with index 1 which is different from the
index in intel_idle driver's internal c-state table.
While intel_idle_max_cstate_reached() was previously introduced to
deal with intel_idle driver's internal c-state table, re-using
this function directly on _CST is incorrect.
Fix this by subtracting 1 from the index when checking max_cstate
in the _CST case.
For example, append intel_idle.max_cstate=1 in boot command line,
Before the patch:
grep . /sys/devices/system/cpu/cpu0/cpuidle/state*/name
POLL
After the patch:
grep . /sys/devices/system/cpu/cpu0/cpuidle/state*/name
/sys/devices/system/cpu/cpu0/cpuidle/state0/name:POLL
/sys/devices/system/cpu/cpu0/cpuidle/state1/name:C1_ACPI
Fixes: 18734958e9bf ("intel_idle: Use ACPI _CST for processor models without C-state tables")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Cc: 5.6+ <stable@vger.kernel.org> # 5.6+
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/idle')
| -rw-r--r-- | drivers/idle/intel_idle.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c index 56f5b8077cba..01bace49a962 100644 --- a/drivers/idle/intel_idle.c +++ b/drivers/idle/intel_idle.c @@ -1239,7 +1239,7 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv) struct acpi_processor_cx *cx; struct cpuidle_state *state; - if (intel_idle_max_cstate_reached(cstate)) + if (intel_idle_max_cstate_reached(cstate - 1)) break; cx = &acpi_state_table.states[cstate]; |