Subject: Re: [PATCH 1/3] thermal: handle get_temp() errors properly
To: Brian Norris <briannorris@chromium.org>
References: <1479513177-81504-1-git-send-email-briannorris@chromium.org>
Cc: Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, Stephen Barber <smbarber@chromium.org>,
        linux-rockchip@lists.infradead.org, Caesar Wang <wxt@rock-chips.com>
From: Caesar Wang <sasukewxt@163.com>
Message-ID: <b798233b-7525-3264-247c-5d9c6374d105@163.com>
Date: Sat, 19 Nov 2016 11:21:39 +0800
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Brian,
在 2016年11月19日 07:52, Brian Norris 写道:
> If using CONFIG_THERMAL_EMULATION, there's a corner case where we might
> get an error from the zone's get_temp() callback, but we'll ignore that
> and keep using its value. Let's just error out properly instead.
>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
Tested-by: Caesar Wang <wxt@rock-chips.com>

[    8.111296] thermal thermal_zone4: power_allocator: sustainable_power 
will be estimated
[    8.119420] thermal_zone_get_temp:537 the ret=-19, no such device, 
look like the A/D value had no ready yet.
..
Anyway, this patch is useful for improving thermal.

-Caesar
> ---
>   drivers/thermal/thermal_core.c | 3 +++
>   1 file changed, 3 insertions(+)
>
> diff --git a/drivers/thermal/thermal_core.c b/drivers/thermal/thermal_core.c
> index 911fd964c742..0fa497f10d25 100644
> --- a/drivers/thermal/thermal_core.c
> +++ b/drivers/thermal/thermal_core.c
> @@ -494,6 +494,8 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
>   	mutex_lock(&tz->lock);
>   
>   	ret = tz->ops->get_temp(tz, temp);
> +	if (ret)
> +		goto exit_unlock;
>   
>   	if (IS_ENABLED(CONFIG_THERMAL_EMULATION) && tz->emul_temperature) {
>   		for (count = 0; count < tz->trips; count++) {
> @@ -514,6 +516,7 @@ int thermal_zone_get_temp(struct thermal_zone_device *tz, int *temp)
>   			*temp = tz->emul_temperature;
>   	}
>    
> +exit_unlock:
>   	mutex_unlock(&tz->lock);
>   exit:
>   	return ret;