On Tue, 17 Jun 2014, Rafael J. Wysocki wrote:

> > diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
> > index e48fc98..8ed93a3 100644
> > --- a/drivers/acpi/battery.c
> > +++ b/drivers/acpi/battery.c
> > @@ -34,6 +34,7 @@
> >  #include <linux/dmi.h>
> >  #include <linux/slab.h>
> >  #include <linux/suspend.h>
> > +#include <linux/delay.h>
> >  #include <asm/unaligned.h>
> >  
> >  #ifdef CONFIG_ACPI_PROCFS_POWER
> > @@ -1119,7 +1120,7 @@ static struct dmi_system_id bat_dmi_table[] = {
> >  
> >  static int acpi_battery_add(struct acpi_device *device)
> >  {
> > -   int result = 0;
> > +   int result = 0, retry = 5;
> >     struct acpi_battery *battery = NULL;
> >  
> >     if (!device)
> > @@ -1135,9 +1136,20 @@ static int acpi_battery_add(struct acpi_device 
> > *device)
> >     mutex_init(&battery->sysfs_lock);
> >     if (acpi_has_method(battery->device->handle, "_BIX"))
> >             set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
> > -   result = acpi_battery_update(battery, false);
> > +
> > +   /*
> > +    * Some machines'(E,G Lenovo Z480) ECs are not stable
> > +    * during boot up and this causes battery driver fails to be
> > +    * probed due to failure of getting battery information
> > +    * from EC sometimes. After several retries, the operation
> > +    * may work. So add retry code here and 20ms sleep between
> > +    * every retries.
> > +    */
> > +   while ((result = acpi_battery_update(battery, false)) && retry--)
> > +           msleep(20);
> >     if (result)
> >             goto fail;
> 
> Why not to write this as
> 
>       for (;;) {
>               result = acpi_battery_update(battery, false);
>               if (!result)
>                       break;
>               else if (!--retry)
>                       goto fail;
> 
>               msleep(20);
>       }
> 

I suggested a similar for loop earlier, I think it's cleaner.
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