cpufreq: amd_freq_sensitivity: Fix sensitivity clamping in amd_powersave_bias_target

The local variable 'sensitivity' was never clamped to 0 or POWERSAVE_BIAS_MAX because the return value of clamp() was not used. Fix this by assigning the clamped value back to 'sensitivity'.

Cc [email protected]

Fixes 9c5320c8ea8b ("cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor")

Signed-off-by Thorsten Blum <[email protected]>

---
 drivers/cpufreq/amd_freq_sensitivity.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

drivers/cpufreq/amd_freq_sensitivity.c +1 -1

index 13fed4b9e02b..713ccf24c97d 100644
@@ -76,7 +76,7 @@ static unsigned int amd_powersave_bias_target(struct cpufreq_policy *policy,
 	sensitivity = POWERSAVE_BIAS_MAX -
 		(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);
 
-	clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
+	sensitivity = clamp(sensitivity, 0, POWERSAVE_BIAS_MAX);
 
 	/* this workload is not CPU bound, so choose a lower freq */
 	if (sensitivity < od_tuners->powersave_bias) {

Quoted 3 lines · On Tue, 2 Dec 2025 13:44:28 +0100 Thorsten Blum <[email protected]>…

The local variable 'sensitivity' was never clamped to 0 or POWERSAVE_BIAS_MAX because the return value of clamp() was not used. Fix this by assigning the clamped value back to 'sensitivity'.

This actually makes no difference
(assuming od_tuners->powersave_bias <= POWERSAVE_BIAS_MAX). The only use of 'sensitivity' is the test at the end of the diff.

So I think you could just delete the line.

Quoted 7 lines · David Laight

Quoted 3 lines · On Tue, 2 Dec 2025 13:44:28 +0100 Thorsten Blum <[email protected]>…

The local variable 'sensitivity' was never clamped to 0 or POWERSAVE_BIAS_MAX because the return value of clamp() was not used. Fix this by assigning the clamped value back to 'sensitivity'.

Quoted 5 lines

This actually makes no difference
(assuming od_tuners->powersave_bias <= POWERSAVE_BIAS_MAX). The only use of 'sensitivity' is the test at the end of the diff.

So I think you could just delete the line.

The local variable 'sensitivity' is an 'int', while '->powersave_bias' is an 'unsigned int'. If 'sensitivity' were ever negative, it would be converted to an 'unsigned int', producing an incorrect result. That's probably what the clamping was meant to prevent.

However, calculating 'sensitivity' can be simplified from:

	sensitivity = POWERSAVE_BIAS_MAX -
		(POWERSAVE_BIAS_MAX * (d_reference - d_actual) / d_reference);

to:

	sensitivity = POWERSAVE_BIAS_MAX * d_actual / d_reference;

which makes it clearer that, in practice, 'sensitivity' is never negative. How about simplifying the formula as above, changing 'sensitivity' to 'unsigned int', and removing the clamping?