From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lan Tianyu Subject: Re: [PATCH] ACPI/Battery: Retry to get Battery information if failed during probing Date: Fri, 13 Jun 2014 10:25:00 +0800 Message-ID: <539A60FC.1050301@intel.com> References: <1402552946-14704-1-git-send-email-tianyu.lan@intel.com> <53995488.20308@intel.com> <53996152.2000407@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mga09.intel.com ([134.134.136.24]:41752 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750862AbaFMCZs (ORCPT ); Thu, 12 Jun 2014 22:25:48 -0400 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: David Rientjes Cc: rjw@rjwysocki.net, lenb@kernel.org, naszar@ya.ru, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org On 2014=E5=B9=B406=E6=9C=8813=E6=97=A5 05:17, David Rientjes wrote: > On Thu, 12 Jun 2014, Lan Tianyu wrote: >=20 >> The retry time is set by randomly and not accurate because don't kno= w >> when EC will work normally. Set the retry time to 5 just in order to >> make sure battery driver probing sucessfully every time, >> >=20 > Ok, I was hoping to avoid the excessive wait if it will never actuall= y=20 > 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,=20 > 60ms, etc. Please consider the following instead: >=20 > for (i =3D 0; i < 5; i++) { > /* Comment on why we need a delay in between retries */ > if (i) > msleep(20); > result =3D acpi_battery_update(battery, false); > if (!result) > break; > } >=20 How about this? - result =3D 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 =3D -ENODEV; goto fail; + } + --=20 Best regards Tianyu Lan -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html