Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758834Ab3DYQNg (ORCPT ); Thu, 25 Apr 2013 12:13:36 -0400 Received: from mail-pd0-f181.google.com ([209.85.192.181]:37467 "EHLO mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757220Ab3DYQNf (ORCPT ); Thu, 25 Apr 2013 12:13:35 -0400 Message-ID: <5179562C.3000903@linaro.org> Date: Thu, 25 Apr 2013 09:13:32 -0700 From: John Stultz User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130329 Thunderbird/17.0.5 MIME-Version: 1.0 To: Alexander Holler CC: Kay Sievers , LKML , Feng Tang , Jason Gunthorpe Subject: Re: CONFIG_RTC_HCTOSYS lost on x86 with ALWAYS_USE_PERSISTENT_CLOCK changes? References: <517746E4.908@linaro.org> <51774F44.2060704@linaro.org> <517769A9.5060308@ahsoftware.de> <51780348.6090202@linaro.org> <5178D719.2060405@ahsoftware.de> In-Reply-To: <5178D719.2060405@ahsoftware.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1196 Lines: 29 On 04/25/2013 12:11 AM, Alexander Holler wrote: > Am 24.04.2013 18:07, schrieb John Stultz: > >>> And why is RTC_SYSTOHC now gone on x86? >> >> So summarizing the above, because as much as I'm aware, its always been >> redundant and unnecessary on x86. Thus being able at build time to mark >> it as unnecessary was attractive, since it reduced the code paths >> running at suspend/resume. > > Hmm, I thought RTC_SYSTOHC was there to update the used RTC clock with > the time from NTP (and liked that). Therefor I don't understand why it > is redundant and unnecessary on x86. Of course, most systems do have > something in userspace to set the RTC on shutdown, so it isn't really > needed. Prior to SYSTOHC being introduced, we only synced system time to the RTC via update_persistent_clock() on systems that had that interface. SYSTOHC is relatively new and lets the system sync to RTCs that don't have the persistent clock. thanks -john -- 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/