On Mon, Feb 20, 2017 at 01:50:14PM +0900, Atsushi Nemoto wrote:
> From: Katsumi Sato <[email protected]>
> 
> Serialize access to the hardware by using "request_muxed_region".
> Call to this macro will hold off the requestor if the resource is
> currently busy. "superio_enter" will return an error if call to
> "request_muxed_region" fails.
> 
> Signed-off-by: Katsumi Sato <[email protected]>
> Signed-off-by: Atsushi Nemoto <[email protected]>
> ---
>  drivers/hwmon/w83627ehf.c |   32 ++++++++++++++++++++++++++------
>  1 files changed, 26 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/hwmon/w83627ehf.c b/drivers/hwmon/w83627ehf.c
> index 697007a..40cb8fa 100644
> --- a/drivers/hwmon/w83627ehf.c
> +++ b/drivers/hwmon/w83627ehf.c
> @@ -135,11 +135,16 @@ enum kinds {
>       outb(ld, ioreg + 1);
>  }
>  
> -static inline void
> +static inline int
>  superio_enter(int ioreg)
>  {
> +     if (!request_muxed_region(ioreg, 2, DRVNAME))
> +             return -EBUSY;
> +
>       outb(0x87, ioreg);
>       outb(0x87, ioreg);
> +
> +     return 0;
>  }
>  
>  static inline void
> @@ -148,6 +153,7 @@ enum kinds {
>       outb(0xaa, ioreg);
>       outb(0x02, ioreg);
>       outb(0x02, ioreg + 1);
> +     release_region(ioreg, 2);
>  }
>  
>  /*
> @@ -1970,7 +1976,10 @@ static void w82627ehf_swap_tempreg(struct 
> w83627ehf_data *data,
>               return;
>       }
>  
> -     superio_enter(sio_data->sioreg);
> +     if (superio_enter(sio_data->sioreg)) {
> +             pr_err("%s: superio is busy!!\n", __func__);
> +             return;
> +     }

This is not good. It effectively ignores the error and does not
initialize the chip's fan configuration. Displaying a log message
doesn't improve the situation.

The best solution here would probably be to remove superio_enter/exit
from this function and move the superio_exit() call in the calling code
after the call to w83627ehf_check_fan_inputs().

>  
>       /* fan4 and fan5 share some pins with the GPIO and serial flash */
>       if (sio_data->kind == nct6775) {
> @@ -2352,7 +2361,11 @@ static int w83627ehf_probe(struct platform_device 
> *pdev)
>       w83627ehf_init_device(data, sio_data->kind);
>  
>       data->vrm = vid_which_vrm();
> -     superio_enter(sio_data->sioreg);
> +
> +     err = superio_enter(sio_data->sioreg);
> +     if (err)
> +             goto exit_release;
> +
>       /* Read VID value */
>       if (sio_data->kind == w83667hg || sio_data->kind == w83667hg_b ||
>           sio_data->kind == nct6775 || sio_data->kind == nct6776) {
> @@ -2364,8 +2377,10 @@ static int w83627ehf_probe(struct platform_device 
> *pdev)
>               superio_select(sio_data->sioreg, W83667HG_LD_VID);
>               data->vid = superio_inb(sio_data->sioreg, 0xe3);
>               err = device_create_file(dev, &dev_attr_cpu0_vid);
> -             if (err)
> +             if (err) {
> +                     superio_exit(sio_data->sioreg);
>                       goto exit_release;
> +             }
>       } else if (sio_data->kind != w83627uhg) {
>               superio_select(sio_data->sioreg, W83627EHF_LD_HWM);
>               if (superio_inb(sio_data->sioreg, SIO_REG_VID_CTRL) & 0x80) {
> @@ -2401,8 +2416,10 @@ static int w83627ehf_probe(struct platform_device 
> *pdev)
>                               data->vid &= 0x3f;
>  
>                       err = device_create_file(dev, &dev_attr_cpu0_vid);
> -                     if (err)
> +                     if (err) {
> +                             superio_exit(sio_data->sioreg);
>                               goto exit_release;
> +                     }
>               } else {
>                       dev_info(dev,
>                                "VID pins in output mode, CPU VID not 
> available\n");
> @@ -2712,8 +2729,11 @@ static int __init w83627ehf_find(int sioaddr, unsigned 
> short *addr,
>  
>       u16 val;
>       const char *sio_name;
> +     int err;
>  
> -     superio_enter(sioaddr);
> +     err = superio_enter(sioaddr);
> +     if (err)
> +             return err;
>  
>       if (force_id)
>               val = force_id;
> -- 
> 
> 
> --
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