Re: [PATCH 1/2] cpufreq: allow cpuinfo max to decrease when boost is disabled

[Zhongqiu Han]

Hi Sibi and Ananthu,

On 8/6/2026 12:42 PM, Sibi Sankar wrote:
> From: Ananthu C V <ananthu.cv@xxxxxxxxxxxxxxxx>
>
> Commit 538b0188da46 ("cpufreq: ACPI: Set cpuinfo.max_freq directly
> if max boost is known") guarded cpuinfo max updates to only allow
> increases, preserving values set directly by drivers above the freq
> table maximum. This prevents cpuinfo max from decreasing on boost
> disable, leaving policy max pinned at the boost ceiling.
>
> Remove the guard so cpuinfo max is always derived from the frequency
> table scan. Drivers that correctly flag boost entries are unaffected
> since the scan already excludes them when boost is off.
>
> Fixes: 538b0188da46 ("cpufreq: ACPI: Set cpuinfo.max_freq directly if max boost is known")
> Signed-off-by: Ananthu C V <ananthu.cv@xxxxxxxxxxxxxxxx>
> Signed-off-by: Sibi Sankar <sibi.sankar@xxxxxxxxxxxxxxxx>
> ---
>   drivers/cpufreq/freq_table.c | 7 +------
>   1 file changed, 1 insertion(+), 6 deletions(-)
>
> diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
> index ea994647abc8..791118466ca4 100644
> --- a/drivers/cpufreq/freq_table.c
> +++ b/drivers/cpufreq/freq_table.c
> @@ -50,12 +50,7 @@ int cpufreq_frequency_table_cpuinfo(struct cpufreq_policy *policy)
>   	}
>   
>   	policy->cpuinfo.min_freq = min_freq;
> -	/*
> -	 * If the driver has set its own cpuinfo.max_freq above max_freq, leave
> -	 * it as is.
> -	 */
> -	if (policy->cpuinfo.max_freq < max_freq)
> -		policy->cpuinfo.max_freq = max_freq;

As I understand it, the guard added by commit 538b0188da46 is
intended for drivers (e.g. acpi-cpufreq and AMD) that may set
cpuinfo.max_freq above the maximum frequency in the frequency table.
Removing it may cause those drivers to lose their boost maximum
frequency.

The regression should instead be related to commit db80ad776cd2
("cpufreq: Remove driver default policy->min/max init"), which removed
the "policy->max = max_freq" initialization that previously allowed
policy->max to track the result of the boost-aware frequency scan.

Please feel free to let me know what you think. Thanks


> +	policy->cpuinfo.max_freq = max_freq;
>   
>   	if (min_freq == ~0)
>   		return -EINVAL;


--
Thx and BRs,
Zhongqiu Han