linux-kernel - Re: [PATCH v2 2/2] platform/x86/drivers/acerhdf: Check the interval value when it is set

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Date:   Thu, 03 Dec 2020 21:22:02 +0000
From:   "Peter Kästle" <peter@...e.net>
To:     "Daniel Lezcano" <daniel.lezcano@...aro.org>, hdegoede@...hat.com,
        mgross@...ux.intel.com
Cc:     platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] platform/x86/drivers/acerhdf: Check the
 interval value when it is set

3. Dezember 2020 08:17, "Daniel Lezcano" <daniel.lezcano@...aro.org> schrieb:

> Currently the code checks the interval value when the temperature is
> read which is bad for two reasons:
> 
> - checking and setting the interval in the get_temp callback is
> inaccurate and awful, that can be done when changing the value.
> 
> - Changing the thermal zone structure internals is an abuse of the
> exported structure, moreover no lock is taken here.
> 
> The goal of this patch is to solve the first item by using the 'set'
> function called when changing the interval. The check is done there
> and removed from the get_temp function. If the thermal zone was not
> initialized yet, the interval is not updated in this case as that will
> happen in the init function when registering the thermal zone device.

Thanks for your effort.  This improves the code, good finding.

 
> I don't have any hardware to test the changes.

Tests successfully executed on my good old AOA110.


> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>

Acked-by: Peter Kaestle <peter@...e.net>


> ---
> V2:
> - Fixed static function annotation
> ---
> drivers/platform/x86/acerhdf.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
> index 19fc8ff2225c..b6aa6e5514f4 100644
> --- a/drivers/platform/x86/acerhdf.c
> +++ b/drivers/platform/x86/acerhdf.c
> @@ -334,7 +334,10 @@ static void acerhdf_check_param(struct thermal_zone_device *thermal)
> }
> if (verbose)
> pr_notice("interval changed to: %d\n", interval);
> - thermal->polling_delay = interval*1000;
> +
> + if (thermal)
> + thermal->polling_delay = interval*1000;
> +
> prev_interval = interval;
> }
> }
> @@ -349,8 +352,6 @@ static int acerhdf_get_ec_temp(struct thermal_zone_device *thermal, int *t)
> {
> int temp, err = 0;
> 
> - acerhdf_check_param(thermal);
> -
> err = acerhdf_get_temp(&temp);
> if (err)
> return err;
> @@ -823,8 +824,21 @@ MODULE_ALIAS("dmi:*:*Acer*:pnExtensa*5420*:");
> module_init(acerhdf_init);
> module_exit(acerhdf_exit);
> 
> +static int interval_set_uint(const char *val, const struct kernel_param *kp)
> +{
> + int ret;
> +
> + ret = param_set_uint(val, kp);
> + if (ret)
> + return ret;
> +
> + acerhdf_check_param(thz_dev);
> +
> + return 0;
> +}
> +
> static const struct kernel_param_ops interval_ops = {
> - .set = param_set_uint,
> + .set = interval_set_uint,
> .get = param_get_uint,
> };
> 
> -- 
> 2.25.1