[PATCH 4.15 013/163] cpufreq: powernv: Dont assume distinct pstate values for nominal and pmin

From: Greg Kroah-Hartman
Date: Wed Feb 21 2018 - 08:06:07 EST


4.15-stable review patch. If anyone has any objections, please let me know.

------------------

From: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>

commit 3fa4680b860bf48b437d6a2c039789c4abe202ae upstream.

Some OpenPOWER boxes can have same pstate values for nominal and
pmin pstates. In these boxes the current code will not initialize
'powernv_pstate_info.min' variable and result in erroneous CPU
frequency reporting. This patch fixes this problem.

Fixes: 09ca4c9b5958 (cpufreq: powernv: Replacing pstate_id with frequency table index)
Reported-by: Alvin Wang <wangat@xxxxxxxxxx>
Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Cc: 4.8+ <stable@xxxxxxxxxxxxxxx> # 4.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/cpufreq/powernv-cpufreq.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/cpufreq/powernv-cpufreq.c
+++ b/drivers/cpufreq/powernv-cpufreq.c
@@ -288,9 +288,9 @@ next:

if (id == pstate_max)
powernv_pstate_info.max = i;
- else if (id == pstate_nominal)
+ if (id == pstate_nominal)
powernv_pstate_info.nominal = i;
- else if (id == pstate_min)
+ if (id == pstate_min)
powernv_pstate_info.min = i;

if (powernv_pstate_info.wof_enabled && id == pstate_turbo) {