On 2014年06月13日 05:17, David Rientjes wrote: > On Thu, 12 Jun 2014, Lan Tianyu wrote: > >> The retry time is set by randomly and not accurate because don't know >> when EC will work normally. Set the retry time to 5 just in order to >> make sure battery driver probing sucessfully every time, >> > > Ok, I was hoping to avoid the excessive wait if it will never actually > succeed Ok. The battery driver has used async init and so this will not affect the speed of boot up. > but I assume there's some evidence that it can succeed after 40ms, > 60ms, etc. Please consider the following instead: > > for (i = 0; i < 5; i++) { > /* Comment on why we need a delay in between retries */ > if (i) > msleep(20); > result = acpi_battery_update(battery, false); > if (!result) > break; > } > How about this? - result = acpi_battery_update(battery, false); - if (result) + + /* + * 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 (acpi_battery_update(battery, false) && retry--) + msleep(20); + if (!retry) { + result = -ENODEV; goto fail; + } + -- Best regards Tianyu Lan -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html