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From: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: linux-hwmon@vger.kernel.org
Subject: Re: [PATCH v5] hwmon: max6650: add thermal cooling device capability
Date: Tue, 23 Apr 2019 08:45:12 -0400	[thread overview]
Message-ID: <45CE0549-CDB8-4655-8309-CEF449FA0730@gmail.com> (raw)
In-Reply-To: <20190422134002.GA18419@roeck-us.net>


> On Apr 22, 2019, at 09:40, Guenter Roeck <linux@roeck-us.net> wrote:
> 
> On a system which has CONFIG_THERMAL enabled but does not really utilize
> it, the call to thermal_cdev_update() will result in the fan being stopped
> immediately since max6650_set_cur_state() is called with state=0.
> 
> I see that this function called from pwm_fan.c. It is not called from
> gpio-fan.c or npcm750-pwm-fan.c. Other than from pwm-fan.c, it is only
> called from thermal governors, and not from any other thermal drivers
> registering a thermal cooling device. This leads me to believe that
> the calls from here and from pwm_fan.c may be wrong.
> 
> Are you sure that this call needed ? If so, can you explain ?
> What happens in your system if you remove this call ?

Yes, you are correct. It is a carry over from pwm-fan.c and so probably wrong
there too. I have tested without the thermal_cdev_update call in probe() and
basically, if the cooling device is not part of a TZ, then set_cur_state is
never called. If part of a TZ, it is called by the governor (step_wise in my
case) as required and all works as expected.

Cheers!




  reply	other threads:[~2019-04-23 12:45 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-19 15:36 [hwmon:hwmon-next 119/119] drivers/hwmon/max6650.c:798:10: warning: passing argument 2 of 'thermal_of_cooling_device_register' discards 'const' qualifier from pointer target type kbuild test robot
2019-04-20  2:56 ` Jean-Francois Dagenais
2019-04-20  3:02 ` [PATCH v5] hwmon: max6650: add thermal cooling device capability Jean-Francois Dagenais
2019-04-22 13:40   ` Guenter Roeck
2019-04-23 12:45     ` Jean-Francois Dagenais [this message]
2019-04-23 13:29       ` Guenter Roeck

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