linux-kernel - Re: [PATCH v2 4/4] acerhdf: Use bang-bang thermal governor

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Date:	Tue, 29 Apr 2014 18:43:07 +0200
From:	Peter Feuerer <peter@...e.net>
To:	Javi Merino <javi.merino@....com>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Zhang Rui <rui.zhang@...el.com>, Andreas Mohr <andi@...as.de>,
	Borislav Petkov <bp@...e.de>
Subject: Re: [PATCH v2 4/4] acerhdf: Use bang-bang thermal governor

Javi Merino writes:

> On Tue, Apr 29, 2014 at 10:17:57AM +0100, Peter Feuerer wrote:
>> acerhdf has been doing an on-off fan control using hysteresis by
>> post-manipulating the outcome of thermal subsystem trip point handling.
>> This patch enables acerhdf to use the bang-bang governor, which is
>> intended for on-off controlled fans.
>> 
>> CC: Zhang Rui <rui.zhang@...el.com>
>> Cc: Andreas Mohr <andi@...as.de>
>> Cc: Borislav Petkov <bp@...e.de>
>> Signed-off-by: Peter Feuerer <peter@...e.net>
>> ---
>>  drivers/platform/x86/Kconfig   |  2 +-
>>  drivers/platform/x86/acerhdf.c | 48 +++++++++++++++++++++++++++++++++++-------
>>  2 files changed, 41 insertions(+), 9 deletions(-)
>> 
>> diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
>> index 27df2c5..0c15d89 100644
>> --- a/drivers/platform/x86/Kconfig
>> +++ b/drivers/platform/x86/Kconfig
>> @@ -38,7 +38,7 @@ config ACER_WMI
>>  
>>  config ACERHDF
>>  	tristate "Acer Aspire One temperature and fan driver"
>> -	depends on THERMAL && ACPI
>> +	depends on ACPI && THERMAL_GOV_BANG_BANG
>>  	---help---
>>  	  This is a driver for Acer Aspire One netbooks. It allows to access
>>  	  the temperature sensor and to control the fan.
>> diff --git a/drivers/platform/x86/acerhdf.c b/drivers/platform/x86/acerhdf.c
>> index 176edbd..f3884f9 100644
>> --- a/drivers/platform/x86/acerhdf.c
>> +++ b/drivers/platform/x86/acerhdf.c
>> @@ -50,7 +50,7 @@
>>   */
>>  #undef START_IN_KERNEL_MODE
>>  
>> -#define DRV_VER "0.5.30"
>> +#define DRV_VER "0.5.31"
>>  
>>  /*
>>   * According to the Atom N270 datasheet,
>> @@ -135,8 +135,8 @@ struct bios_settings_t {
>>  	const char *vendor;
>>  	const char *product;
>>  	const char *version;
>> -	unsigned char fanreg;
>> -	unsigned char tempreg;
>> +	u8 fanreg;
>> +	u8 tempreg;
>>  	struct fancmd cmd;
>>  	int mcmd_enable;
>>  };
>> @@ -259,6 +259,17 @@ static const struct bios_settings_t bios_tbl[] = {
>>  
>>  static const struct bios_settings_t *bios_cfg __read_mostly;
>>  
>> +/*
>> + * this struct is used to instruct thermal layer to use bang_bang instead of
>> + * default governor for acerhdf
>> + */
>> +static struct thermal_zone_params acerhdf_zone_params = {
>> +	.governor_name = "bang_bang",
>> +	.no_hwmon = 0,
>> +	.num_tbps = 0,
>> +	.tbp = 0,
>> +};
> 
> You don't need to initialize statics to 0.  checkpatch only considers
> it an error if it finds it in a variable, but I think it also applies
> to fields in struct.

I agree, this is superfluous.  I'll remove those lines.


>> +
>>  static int acerhdf_get_temp(int *temp)
>>  {
>>  	u8 read_temp;
>> @@ -436,6 +447,17 @@ static int acerhdf_get_trip_type(struct thermal_zone_device *thermal, int trip,
>>  {
>>  	if (trip == 0)
>>  		*type = THERMAL_TRIP_ACTIVE;
>> +	if (trip == 1)
>> +		*type = THERMAL_TRIP_CRITICAL;
> 
> This looks like an unrelated change that should be on a patch on its
> own.

Yes, will do so.



>> +
>> +	return 0;
>> +}
>> +
>> +static int acerhdf_get_trip_hyst(struct thermal_zone_device *thermal, int trip,
>> +				 unsigned long *temp)
>> +{
>> +	if (trip == 0)
>> +		*temp = fanon - fanoff;
>>  
>>  	return 0;
>>  }
>> @@ -445,6 +467,8 @@ static int acerhdf_get_trip_temp(struct thermal_zone_device *thermal, int trip,
>>  {
>>  	if (trip == 0)
>>  		*temp = fanon;
>> +	else if (trip == 1)
>> +		*temp = ACERHDF_TEMP_CRIT;
>>  
>>  	return 0;
>>  }
>> @@ -464,8 +488,10 @@ static struct thermal_zone_device_ops acerhdf_dev_ops = {
>>  	.get_mode = acerhdf_get_mode,
>>  	.set_mode = acerhdf_set_mode,
>>  	.get_trip_type = acerhdf_get_trip_type,
>> +	.get_trip_hyst = acerhdf_get_trip_hyst,
>>  	.get_trip_temp = acerhdf_get_trip_temp,
>>  	.get_crit_temp = acerhdf_get_crit_temp,
>> +	.notify = NULL,
> 
> Same as before, no need to initialize static to NULL.

Ok, thanks.

-- 
kind regards,
--peter; 
--
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