[PATCH 5.7 096/112] thermal/drivers/cpufreq_cooling: Fix wrong frequency converted from power

Greg Kroah-Hartman
2020-07-07T15:27:28Z

From: Finley Xiao <finley.xiao@rock-chips.com>

commit 371a3bc79c11b707d7a1b7a2c938dc3cc042fffb upstream.

The function cpu_power_to_freq is used to find a frequency and set the
cooling device to consume at most the power to be converted. For example,
if the power to be converted is 80mW, and the em table is as follow.
struct em_cap_state table[] = {
/* KHz mW */
{ 1008000, 36, 0 },
{ 1200000, 49, 0 },
{ 1296000, 59, 0 },
{ 1416000, 72, 0 },
{ 1512000, 86, 0 },
};
The target frequency should be 1416000KHz, not 1512000KHz.

Fixes: 349d39dc5739 ("thermal: cpu_cooling: merge frequency and power tables")
Cc: <stable@vger.kernel.org> # v4.13+
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20200619090825.32747-1-finley.xiao@rock-chips.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/thermal/cpufreq_cooling.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/thermal/cpufreq_cooling.c
+++ b/drivers/thermal/cpufreq_cooling.c
@@ -123,12 +123,12 @@ static u32 cpu_power_to_freq(struct cpuf
{
int i;

- for (i = cpufreq_cdev->max_level - 1; i >= 0; i--) {
- if (power > cpufreq_cdev->em->table[i].power)
+ for (i = cpufreq_cdev->max_level; i >= 0; i--) {
+ if (power >= cpufreq_cdev->em->table[i].power)
break;
}

- return cpufreq_cdev->em->table[i + 1].frequency;
+ return cpufreq_cdev->em->table[i].frequency;
}

/**