On Tuesday 09 December 2014 21:20:23 Guenter Roeck wrote:
> On Tue, Dec 09, 2014 at 09:07:00PM +0100, Pali Rohár wrote:
> > This patch adds new function i8k_get_fan_nominal_rpm() for
> > doing SMM call which will return nominal fan RPM for
> > specified fan speed. It returns nominal RPM value at which
> > fan operate when speed is set. It looks like RPM value is
> > not accurate, but still provides very useful information.
> > 
> > First it can be used to validate if certain fan speed could
> > be accepted by SMM for setting fan speed and we can use
> > this routine to detect maximal fan speed.
> > 
> > Second it returns RPM value, so we can check if value looks
> > correct with multiplier 30 or multiplier 1 (until now only
> > these two multiplier was used). If RPM value with
> > multiplier 30 is too high, then multiplier 1 is used.
> > 
> > In case when SMM reports that new function is not supported
> > we will fallback to old hardcoded values. Maximal fan speed
> > would be 2 and RPM multiplier 30.
> > 
> > Signed-off-by: Pali Rohár <[email protected]>
> > ---
> > I tested this patch only on my Dell Latitude E6440 and
> > autodetection worked fine Before appying this patch it
> > should be tested on some other dell machines too but if
> > machine does not support i8k_get_fan_nominal_rpm() driver
> > should fallback to old values. So patch should be without
> > regressions.
> 
> It looks like many of your error checks are unnecessary.
> Why did you add those ?
> 
> Please refrain from adding unnecessary code.
> 
> Guenter
> 

Which error checks do you mean?

> > ---
> > 
> >  drivers/char/i8k.c       |  122
> >  ++++++++++++++++++++++++++++++++++++++--------
> >  include/uapi/linux/i8k.h |    4 +-
> >  2 files changed, 104 insertions(+), 22 deletions(-)
> > 
> > diff --git a/drivers/char/i8k.c b/drivers/char/i8k.c
> > index 31e4beb..8bdbed2 100644
> > --- a/drivers/char/i8k.c
> > +++ b/drivers/char/i8k.c
> > @@ -42,12 +42,14 @@
> > 
> >  #define I8K_SMM_GET_FAN_SPEED      0x00a3
> >  #define I8K_SMM_SET_FAN_SPEED      0x01a3
> >  #define I8K_SMM_GET_FAN_RPM        0x02a3
> > 
> > +#define I8K_SMM_GET_FAN_NOM_RPM    0x04a3
> > 
> >  #define I8K_SMM_GET_TEMP   0x10a3
> >  #define I8K_SMM_GET_TEMP_TYPE      0x11a3
> >  #define I8K_SMM_GET_DELL_SIG1      0xfea3
> >  #define I8K_SMM_GET_DELL_SIG2      0xffa3
> > 
> > -#define I8K_FAN_MULT               30
> > +#define I8K_FAN_DEFAULT_MULT       30
> > +#define I8K_FAN_MAX_RPM            30000
> > 
> >  #define I8K_MAX_TEMP               127
> >  
> >  #define I8K_FN_NONE                0x00
> > 
> > @@ -64,9 +66,9 @@ static DEFINE_MUTEX(i8k_mutex);
> > 
> >  static char bios_version[4];
> >  static struct device *i8k_hwmon_dev;
> >  static u32 i8k_hwmon_flags;
> > 
> > -static int i8k_fan_mult;
> > -static int i8k_pwm_mult;
> > -static int i8k_fan_max = I8K_FAN_HIGH;
> > +static int i8k_fan_mult[I8K_FAN_COUNT];
> > +static int i8k_pwm_mult[I8K_FAN_COUNT];
> > +static int i8k_fan_max[I8K_FAN_COUNT];
> > 
> >  #define I8K_HWMON_HAVE_TEMP1       (1 << 0)
> >  #define I8K_HWMON_HAVE_TEMP2       (1 << 1)
> > 
> > @@ -95,13 +97,13 @@ static bool power_status;
> > 
> >  module_param(power_status, bool, 0600);
> >  MODULE_PARM_DESC(power_status, "Report power status in
> >  /proc/i8k");
> > 
> > -static int fan_mult = I8K_FAN_MULT;
> > +static int fan_mult;
> > 
> >  module_param(fan_mult, int, 0);
> > 
> > -MODULE_PARM_DESC(fan_mult, "Factor to multiply fan rpm
> > with"); +MODULE_PARM_DESC(fan_mult, "Factor to multiply fan
> > rpm with (default: autodetect)");
> > 
> > -static int fan_max = I8K_FAN_HIGH;
> > +static int fan_max;
> > 
> >  module_param(fan_max, int, 0);
> > 
> > -MODULE_PARM_DESC(fan_max, "Maximum configurable fan
> > speed"); +MODULE_PARM_DESC(fan_max, "Maximum configurable
> > fan speed (default: autodetect)");
> > 
> >  static int i8k_open_fs(struct inode *inode, struct file
> >  *file); static long i8k_ioctl(struct file *, unsigned int,
> >  unsigned long);
> > 
> > @@ -271,8 +273,25 @@ static int i8k_get_fan_rpm(int fan)
> > 
> >  {
> >  
> >     struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_RPM, };
> > 
> > +   if (fan < 0 || fan >= I8K_FAN_COUNT)
> > +           return -EINVAL;
> > +
> > 
> >     regs.ebx = fan & 0xff;
> > 
> > -   return i8k_smm(&regs) ? : (regs.eax & 0xffff) *
> > i8k_fan_mult; +     return i8k_smm(&regs) ? : (regs.eax &
> > 0xffff) * i8k_fan_mult[fan]; +}
> > +
> > +/*
> > + * Read the fan nominal rpm for specific fan speed.
> > + */
> > +static int i8k_get_fan_nominal_rpm(int fan, int speed)
> > +{
> > +   struct smm_regs regs = { .eax = I8K_SMM_GET_FAN_NOM_RPM,
> > }; +
> > +   if (fan < 0 || fan >= I8K_FAN_COUNT)
> > +           return -EINVAL;
> > +
> > +   regs.ebx = (fan & 0xff) | (speed << 8);
> > +   return i8k_smm(&regs) ? : (regs.eax & 0xffff) *
> > i8k_fan_mult[fan];
> > 
> >  }
> >  
> >  /*
> > 
> > @@ -282,9 +301,12 @@ static int i8k_set_fan_speed(int fan,
> > int speed)
> > 
> >  {
> >  
> >     struct smm_regs regs = { .eax = I8K_SMM_SET_FAN_SPEED, };
> > 
> > -   speed = (speed < 0) ? 0 : ((speed > i8k_fan_max) ?
> > i8k_fan_max : speed); -     regs.ebx = (fan & 0xff) | (speed <<
> > 8);
> > +   if (speed < 0)
> > +           speed = 0;
> > +   if (fan >= 0 && fan < I8K_FAN_COUNT && speed >
> > i8k_fan_max[fan]) +         speed = i8k_fan_max[fan];
> > 
> > +   regs.ebx = (fan & 0xff) | (speed << 8);
> > 
> >     return i8k_smm(&regs) ? : i8k_get_fan_speed(fan);
> >  
> >  }
> > 
> > @@ -559,10 +581,14 @@ static ssize_t
> > i8k_hwmon_show_pwm(struct device *dev,
> > 
> >     int index = to_sensor_dev_attr(devattr)->index;
> >     int fan_speed;
> > 
> > +   if (index < 0 || index >= I8K_FAN_COUNT)
> > +           return -EINVAL;
> > +
> > 
> >     fan_speed = i8k_get_fan_speed(index);
> >     if (fan_speed < 0)
> >     
> >             return -EIO;
> > 
> > -   return sprintf(buf, "%d\n", clamp_val(fan_speed *
> > i8k_pwm_mult, 0, 255)); +   return sprintf(buf, "%d\n",
> > clamp_val(fan_speed * i8k_pwm_mult[index], +                                
> >         
      0,
> > 255));
> > 
> >  }
> >  
> >  static ssize_t i8k_hwmon_set_pwm(struct device *dev,
> > 
> > @@ -573,10 +599,14 @@ static ssize_t
> > i8k_hwmon_set_pwm(struct device *dev,
> > 
> >     unsigned long val;
> >     int err;
> > 
> > +   if (index < 0 || index >= I8K_FAN_COUNT)
> > +           return -EINVAL;
> > +
> > 
> >     err = kstrtoul(buf, 10, &val);
> >     if (err)
> >     
> >             return err;
> > 
> > -   val = clamp_val(DIV_ROUND_CLOSEST(val, i8k_pwm_mult), 0,
> > i8k_fan_max); +     val = clamp_val(DIV_ROUND_CLOSEST(val,
> > i8k_pwm_mult[index]), 0, +                  i8k_fan_max[index]);
> > 
> >     mutex_lock(&i8k_mutex);
> >     err = i8k_set_fan_speed(index, val);
> > 
> > @@ -854,7 +884,9 @@ MODULE_DEVICE_TABLE(dmi, i8k_dmi_table);
> > 
> >   */
> >  
> >  static int __init i8k_probe(void)
> >  {
> > 
> > +   const struct i8k_config_data *conf;
> > 
> >     const struct dmi_system_id *id;
> > 
> > +   int fan, val, ret;
> > 
> >     /*
> >     
> >      * Get DMI information
> > 
> > @@ -883,18 +915,66 @@ static int __init i8k_probe(void)
> > 
> >                     return -ENODEV;
> >     
> >     }
> > 
> > -   i8k_fan_mult = fan_mult;
> > -   i8k_fan_max = fan_max ? : I8K_FAN_HIGH; /* Must not be 0
> > */ +        /*
> > +    * Autodetect fan multiplier and maximal fan speed from
> > dmi config +         * Values specified in module parameters
> > override values from dmi +   */
> > 
> >     id = dmi_first_match(i8k_dmi_table);
> >     if (id && id->driver_data) {
> > 
> > -           const struct i8k_config_data *conf = id->driver_data;
> > +           conf = id->driver_data;
> > +           if (fan_mult <= 0 && conf->fan_mult > 0)
> > +                   fan_mult = conf->fan_mult;
> > +           if (fan_max <= 0 && conf->fan_max > 0)
> > +                   fan_max = conf->fan_max;
> > +   }
> > 
> > -           if (fan_mult == I8K_FAN_MULT && conf->fan_mult)
> > -                   i8k_fan_mult = conf->fan_mult;
> > -           if (fan_max == I8K_FAN_HIGH && conf->fan_max)
> > -                   i8k_fan_max = conf->fan_max;
> > +   if (fan_mult <= 0) {
> > +           /*
> > +            * Autodetect fan multiplier for each fan based on
> > nominal rpm +                * First set default fan multiplier for each
> > fan +                * And if it reports rpm value too high then set
> > multiplier to 1 +            */
> > +           for (fan = 0; fan < I8K_FAN_COUNT; ++fan) {
> > +                   i8k_fan_mult[fan] = I8K_FAN_DEFAULT_MULT;
> > +                   for (val = 0; val < 256; ++val) {
> > +                           ret = i8k_get_fan_nominal_rpm(fan, val);
> > +                           if (ret > I8K_FAN_MAX_RPM) {
> > +                                   i8k_fan_mult[fan] = 1;
> > +                                   break;
> > +                           } else if (ret < 0) {
> > +                                   break;
> > +                           }
> > +                   }
> > +           }
> > +   } else {
> > +           /* Fan multiplier was specified in module param or in 
dmi
> > */ +                for (fan = 0; fan < I8K_FAN_COUNT; ++fan)
> > +                   i8k_fan_mult[fan] = fan_mult;
> > 
> >     }
> > 
> > -   i8k_pwm_mult = DIV_ROUND_UP(255, i8k_fan_max);
> > +
> > +   if (fan_max <= 0) {
> > +           /*
> > +            * Autodetect maximal fan speed value for each fan
> > +            * Speed value is valid if i8k_get_fan_nominal_rpm() 
not
> > fail +               */
> > +           for (fan = 0; fan < I8K_FAN_COUNT; ++fan) {
> > +                   for (val = 0; val < 256; ++val) {
> > +                           if (i8k_get_fan_nominal_rpm(fan, val) < 0)
> > +                                   break;
> > +                   }
> > +                   --val; /* set last value which not failed */
> > +                   if (val <= 0) /* Must not be 0 (and non negative) 
*/
> > +                           val = I8K_FAN_HIGH;
> > +                   i8k_fan_max[fan] = val;
> > +           }
> > +   } else {
> > +           /* Maximal fan speed was specified in module param or 
in
> > dmi */ +            for (fan = 0; fan < I8K_FAN_COUNT; ++fan)
> > +                   i8k_fan_max[fan] = fan_max;
> > +   }
> > +
> > +   for (fan = 0; fan < I8K_FAN_COUNT; ++fan)
> > +           i8k_pwm_mult[fan] = DIV_ROUND_UP(255, 
i8k_fan_max[fan]);
> > 
> >     return 0;
> >  
> >  }
> > 
> > diff --git a/include/uapi/linux/i8k.h
> > b/include/uapi/linux/i8k.h index 133d02f..60ef0ea 100644
> > --- a/include/uapi/linux/i8k.h
> > +++ b/include/uapi/linux/i8k.h
> > @@ -29,8 +29,10 @@
> > 
> >  #define I8K_GET_FAN                _IOWR('i', 0x86, size_t)
> >  #define I8K_SET_FAN                _IOWR('i', 0x87, size_t)
> > 
> > -#define I8K_FAN_LEFT               1
> > 
> >  #define I8K_FAN_RIGHT              0
> > 
> > +#define I8K_FAN_LEFT               1
> > +#define I8K_FAN_COUNT              (I8K_FAN_LEFT + 1)
> > +
> > 
> >  #define I8K_FAN_OFF                0
> >  #define I8K_FAN_LOW                1
> >  #define I8K_FAN_HIGH               2

-- 
Pali Rohár
[email protected]

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