On Wednesday, June 18, 2014 03:15:47 PM David Rientjes wrote:
> 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.
Precisely. And it would be even more clean to introduce
static bool acpi_battery_update_retry(struct acpi_battery *battery)
{
int retry, ret;
for (retry = 5; retry; retry--) {
ret = acpi_battery_update(battery, false);
if (!ret)
break;
msleep(20);
}
return ret;
}
and use that instead of the open-coded loop.
Rafael
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