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SubjectRe: [PATCH 4.19 123/133] thermal/drivers/cpufreq_cooling: Fix wrong frequency converted from power
Hi!

> 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.

It is possible that table is always sorted in the opposite direction
in 4.19...

@@ -86,7 +72,7 @@ struct cpufreq_cooling_device {
- struct freq_table *freq_table; /* In descending order */

(This was changed by a4e893e802e6a807df2e2f3f660f7399bc7e104e).

> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -278,11 +278,11 @@ static u32 cpu_power_to_freq(struct cpuf
> int i;
> struct freq_table *freq_table = cpufreq_cdev->freq_table;
>
> - for (i = 1; i <= cpufreq_cdev->max_level; i++)
> - if (power > freq_table[i].power)
> + for (i = 0; i < cpufreq_cdev->max_level; i++)
> + if (power >= freq_table[i].power)
> break;
>
> - return freq_table[i - 1].frequency;
> + return freq_table[i].frequency;
> }

In that case the patch makes some sense.

Best regards,
Pavel
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
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