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authorChen Yu <yu.c.chen@intel.com>2020-10-25 00:29:53 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2020-10-27 19:03:53 +0100
commit4e0ba5577dba686f96c1c10ef4166380667fdec7 (patch)
treef7234fa8ab802e6d76c885b486857046af8523a3 /drivers/idle
parent3650b228f83adda7e5ee532e2b90429c03f7b9ec (diff)
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.c2
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];