From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753278AbbBMOXF (ORCPT ); Fri, 13 Feb 2015 09:23:05 -0500 Received: from v094114.home.net.pl ([79.96.170.134]:63563 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752797AbbBMOXD (ORCPT ); Fri, 13 Feb 2015 09:23:03 -0500 From: "Rafael J. Wysocki" To: Viresh Kumar Cc: Thomas Gleixner , Linaro Kernel Mailman List , Linux Kernel Mailing List , Kevin Hilman , Frederic Weisbecker , Preeti U Murthy , Daniel Lezcano , Linaro Networking , Peter Zijlstra Subject: Re: [PATCH v2] clockevents: Introduce mode specific callbacks Date: Fri, 13 Feb 2015 15:46:11 +0100 Message-ID: <1757256.KD83W4bJsz@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/3.19.0+; KDE/4.11.5; x86_64; ; ) In-Reply-To: References: <792d59a40423f0acffc9bb0bec9de1341a06fa02.1423788565.git.viresh.kumar@linaro.org> <1911031.mQ9ZbsnC1C@vostro.rjw.lan> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, February 13, 2015 11:01:18 AM Viresh Kumar wrote: > On 13 February 2015 at 10:11, Rafael J. Wysocki wrote: > > On Friday, February 13, 2015 08:54:56 AM Viresh Kumar wrote: > >> It is not possible for the clockevents core to know which modes (other than > >> those with a corresponding feature flag) are supported by a particular > >> implementation. And drivers are expected to handle transition to all modes > >> elegantly, as ->set_mode() would be issued for them unconditionally. > >> > >> Now, adding support for a new mode complicates things a bit if we want to use > >> the legacy ->set_mode() callback. We need to closely review all clockevents > >> drivers to see if they would break on addition of a new mode. And after such > >> reviews, it is found that we have to do non-trivial changes to most of the > >> drivers [1]. > >> > >> Introduce mode-specific set_mode_*() callbacks, some of which the drivers may or > >> may not implement. A missing callback would clearly convey the message that the > >> corresponding mode isn't supported. > > > > This is not going to fly AFAICS if you don't say what exacly you need it for. > > For this: https://lkml.org/lkml/2014/5/9/508 OK, I see. -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center.