Re: [PATCH v1 2/2] PM: devfreq: handle invalid parameters gracefully in simpleondemand

[Chanwoo Choi <chanwoo@kernel.org>]

25. 11. 18. 12:23에 Riwen Lu 이(가) 쓴 글:
> Instead of returning -EINVAL when upthreshold > 100 or upthreshold <
> downdifferential, fall back to default threshold values to ensure the
> governor continues functioning.
> 
> Additionally, the validation is now scoped to the if (data) block,
> preventing unnecessary checks when no user data is provided, while the
> fallback mechanism ensures reliability with invalid configurations.
> 
> Signed-off-by: Riwen Lu <luriwen@kylinos.cn>
> ---
>  drivers/devfreq/governor_simpleondemand.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/devfreq/governor_simpleondemand.c b/drivers/devfreq/governor_simpleondemand.c
> index b4d7be766f33..7205891d2ec6 100644
> --- a/drivers/devfreq/governor_simpleondemand.c
> +++ b/drivers/devfreq/governor_simpleondemand.c
> @@ -36,10 +36,15 @@ static int devfreq_simple_ondemand_func(struct devfreq *df,
>  			dfso_upthreshold = data->upthreshold;
>  		if (data->downdifferential)
>  			dfso_downdifferential = data->downdifferential;
> +
> +		if (dfso_upthreshold > 100 ||
> +		    dfso_upthreshold < dfso_downdifferential) {
> +			dfso_upthreshold = DFSO_UPTHRESHOLD;
> +			dfso_downdifferential = DFSO_DOWNDIFFERENTIAL;
> +			pr_debug("Invalid thresholds, using defaults: up = %u, down = %u\n",
> +				dfso_upthreshold, dfso_downdifferential);
> +		}
>  	}
> -	if (dfso_upthreshold > 100 ||
> -	    dfso_upthreshold < dfso_downdifferential)
> -		return -EINVAL;
>  
>  	/* Assume MAX if it is going to be divided by zero */
>  	if (stat->total_time == 0) {

If there are wrong initialization of devfreq_simple_ondemand,
it should point out what is wrong because it makes some confusion if there are no error.


-- 
Best Regards,
Samsung Electronics
Chanwoo Choi