Re: [RFC v3] asus-wmi: add fan control

[Darren Hart <dvhart@infradead.org>]

On Sun, May 10, 2015 at 11:12:38PM +0200, Kast Bernd wrote:
> This patch is partially based on Felipe Contrera's earlier patch, that
> was discussed here: https://lkml.org/lkml/2013/10/8/800
> Some problems of that patch are solved, now:
> 
> 1) The main obstacle for the earlier patch seemed to be the use of
> virt_to_phys, which is accepted, now
> 
> 2) random memory corruption occurred on my notebook, thus DMA-able memory
> is allocated now, which solves this problem
> 
> 3) hwmon interface is used instead of the thermal interface, as a
> hwmon device is already set up by this driver and seemed more
> appropriate than the thermal interface
> 
> 4) Calling the ACPI-functions was modularized thus it's possible to call
> some multifunctions easily, now (by using
> asus_wmi_evaluate_method_agfn).
> 
> Unfortunately the WMI doesn't support controlling both fans on
> a dual-fan notebook because of an restriction in the acpi-method
> "SFNS", that is callable through the wmi. If "SFNV" would be called
> directly even dual fan configurations could be controlled, but not by using
> wmi.
> 
> Speed readings only work on auto-mode, thus "-1" will be reported in
> manual mode.
> Additionally the speed readings are reported as hundreds of RPM thus
> they are not too precise.
> 
> This patch is tested only on one notebook (N551JK) but a similar module,
> that contained some code to try to control the second fan also, was
> reported to work on an UX32VD, at least for the first fan.
> 
> As Felipe already mentioned the low-level functions are described here:
> http://forum.notebookreview.com/threads/fan-control-on-asus-prime-ux31-ux31a-ux32a-ux32vd.705656/
> 
> Signed-off-by: Kast Bernd <kastbernd@gmx.de>
> Cc: Corentin Chary <corentin.chary@gmail.com>
> Cc: Darren Hart <dvhart@infradead.org>
> Cc: Matthew Garrett <mjg59@srcf.ucam.org>
> Cc: Rafael J. Wysocki <rjw@rjwysocki.net>

Hi Kast,

Seeing a build warning on my merge:

C      drivers/platform/x86/asus-wmi.o
drivers/platform/x86/asus-wmi.c: In function ‘pwm1_enable_store’:
drivers/platform/x86/asus-wmi.c:1279:2: warning: ignoring return value of ‘kstrtouint’, declared with attribute warn_unused_result [-Wunused-result]
  kstrtouint(buf, 10, &state);
  ^
drivers/platform/x86/asus-wmi.c: In function ‘pwm1_store’:
drivers/platform/x86/asus-wmi.c:1237:2: warning: ignoring return value of ‘kstrtouint’, declared with attribute warn_unused_result [-Wunused-result]
  kstrtouint(buf, 10, &value);

Please be sure to watch for newly introduced warnings in the build before
submitting patches.

Also, missed two nits below which I'm bringing up mostly because you will need
to respin to fix the warning above anyway.

> Changes for v3:
> 	suggested by Darren Hart:
> 		- changed formating of multi-line comment blocks
> 		- changed return paths
> 		- changed confusing variable name
> Changes for v2:
>         suggested by Darren Hart:
>                 - variable ordering from longest to shortest
>                 - fail label removed in asus_wmi_evaluate_method_agfn
>                 - removed unnecessary ternary operator
>                 - used NULL instead of 0
>                 - used DEVICE_ATTR_(RO|RW)
>         suggested by Corentin Chary:
>                 - asus_hwmon_agfn_fan_speed split to two functions
>                 - added some logging
>                 - used existing function to clamp values
>         suggested by both:
>                 - updated comments
>                 - tried to return proper error codes
>                 - removed some magic numbers
> I'm really sorry, that there are that many style issues in my code. 
> Thank you, that you spent your time reviewing it, nevertheless.
> 
>  drivers/platform/x86/asus-wmi.c | 331 +++++++++++++++++++++++++++++++++++++---
>  1 file changed, 310 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 7543a56..c134b84 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -78,6 +78,7 @@ MODULE_LICENSE("GPL");
>  #define ASUS_WMI_METHODID_GPID		0x44495047 /* Get Panel ID?? (Resol) */
>  #define ASUS_WMI_METHODID_QMOD		0x444F4D51 /* Quiet MODe */
>  #define ASUS_WMI_METHODID_SPLV		0x4C425053 /* Set Panel Light Value */
> +#define ASUS_WMI_METHODID_AGFN		0x4E464741 /* FaN? */
>  #define ASUS_WMI_METHODID_SFUN		0x4E554653 /* FUNCtionalities */
>  #define ASUS_WMI_METHODID_SDSP		0x50534453 /* Set DiSPlay output */
>  #define ASUS_WMI_METHODID_GDSP		0x50534447 /* Get DiSPlay output */
> @@ -150,12 +151,39 @@ MODULE_LICENSE("GPL");
>  #define ASUS_WMI_DSTS_BRIGHTNESS_MASK	0x000000FF
>  #define ASUS_WMI_DSTS_MAX_BRIGTH_MASK	0x0000FF00
>  
> +#define ASUS_FAN_DESC			"cpu_fan"
> +#define ASUS_FAN_MFUN			0x13
> +#define ASUS_FAN_SFUN_READ		0x06
> +#define ASUS_FAN_SFUN_WRITE		0x07
> +#define ASUS_FAN_CTRL_MANUAL		1
> +#define ASUS_FAN_CTRL_AUTO		2
> +
> +
>  struct bios_args {
>  	u32 arg0;
>  	u32 arg1;
>  } __packed;
>  
>  /*
> + * Struct that's used for all methods called via AGFN. Naming is
> + * identically to the AML code.
> + */
> +struct agfn_args {
> +	u16 mfun; /* probably "Multi-function" to be called */
> +	u16 sfun; /* probably "Sub-function" to be called */
> +	u16 len;  /* size of the hole struct, including subfunction fields */
> +	u8 stas;  /* not used by now */
> +	u8 err;   /* zero on success */
> +} __packed;
> +
> +/* struct used for calling fan read and write methods */
> +struct fan_args {
> +	struct agfn_args agfn;	/* common fields */
> +	u8 fan;			/* fan number: 0: set auto mode 1: 1st fan */
> +	u32 speed;		/* read: RPM/100 - write: 0-255 */
> +} __packed;
> +
> +/*
>   * <platform>/    - debugfs root directory
>   *   dev_id      - current dev_id
>   *   ctrl_param  - current ctrl_param
> @@ -204,6 +232,10 @@ struct asus_wmi {
>  	struct asus_rfkill gps;
>  	struct asus_rfkill uwb;
>  
> +	int asus_hwmon_pwm;
> +	int asus_hwmon_num_fans;
> +	bool asus_hwmon_fan_manual_mode;

Declare in order of decreasing line length please:

	bool asus_hwmon_fan_manual_mode;
	int asus_hwmon_num_fans;
	int asus_hwmon_pwm;

> +
>  	struct hotplug_slot *hotplug_slot;
>  	struct mutex hotplug_lock;
>  	struct mutex wmi_lock;
> @@ -294,6 +326,35 @@ exit:
>  	return 0;
>  }
>  
> +static int asus_wmi_evaluate_method_agfn(const struct acpi_buffer args)
> +{
> +	struct acpi_buffer input;
> +	u64 phys_addr;
> +	u32 retval;
> +	u32 status = -1;
> +
> +	/* Copy to dma capable address otherwise memory corruption occurs as
> +	 * bios has to be able to access it.
> +	 */

Multiline comment blocks should have an empty /* line to start:

/*
 * First line.
 * Second line.
 */

See CodingStyle:Chapter 8:Commenting

Thanks,

-- 
Darren Hart
Intel Open Source Technology Center