Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751283AbaFMCZv (ORCPT ); Thu, 12 Jun 2014 22:25:51 -0400 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 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,468,1400050800"; d="scan'208";a="527732909" Message-ID: <539A60FC.1050301@intel.com> Date: Fri, 13 Jun 2014 10:25:00 +0800 From: Lan Tianyu User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 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 Subject: Re: [PATCH] ACPI/Battery: Retry to get Battery information if failed during probing References: <1402552946-14704-1-git-send-email-tianyu.lan@intel.com> <53995488.20308@intel.com> <53996152.2000407@intel.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/