Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756479AbaFSGtJ (ORCPT ); Thu, 19 Jun 2014 02:49:09 -0400 Received: from mga11.intel.com ([192.55.52.93]:25202 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753266AbaFSGtI (ORCPT ); Thu, 19 Jun 2014 02:49:08 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.01,505,1400050800"; d="scan'208";a="557788797" Message-ID: <53A287A9.7000203@intel.com> Date: Thu, 19 Jun 2014 14:48:09 +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: "Rafael J. Wysocki" CC: David Rientjes , lenb@kernel.org, naszar@ya.ru, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V2] ACPI/Battery: Retry to get Battery information if failed during probing References: <1402988994-27067-1-git-send-email-tianyu.lan@intel.com> <1474004.fDjayHqHT9@vostro.rjw.lan> <2223803.V8Foed99uq@vostro.rjw.lan> In-Reply-To: <2223803.V8Foed99uq@vostro.rjw.lan> 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19日 07:00, Rafael J. Wysocki wrote: > 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 >>>> #include >>>> #include >>>> +#include >>>> #include >>>> >>>> #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. Ok. I will update patch like this. > > Rafael > -- 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/