From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752563Ab3C1ReS (ORCPT ); Thu, 28 Mar 2013 13:34:18 -0400 Received: from mail-we0-f173.google.com ([74.125.82.173]:40253 "EHLO mail-we0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751643Ab3C1ReR (ORCPT ); Thu, 28 Mar 2013 13:34:17 -0400 Date: Thu, 28 Mar 2013 18:34:00 +0100 From: Richard GENOUD To: Stephen Warren Cc: Linus Walleij , Stephen Warren , linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/4] pinctrl: re-enable old state in case of error in pinctrl_select_state Message-ID: <20130328173356.GA10420@lnx-rg> References: <1364222843-30305-1-git-send-email-richard.genoud@gmail.com> <1364222843-30305-5-git-send-email-richard.genoud@gmail.com> <51538701.60409@wwwdotorg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <51538701.60409@wwwdotorg.org> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On [mer., 27.03.2013 17:55:45], Stephen Warren wrote: > On 03/25/2013 08:47 AM, Richard Genoud wrote: > > If a new state is applied, the groups configured in the old state but > > not in the new state are disabled. > > If something goes wrong and the new state can't be applied, we have to > > re-enable those groups. > > What is the use-case for this? I wonder if it isn't better to simply > undo the partial selection of the new state (as patch 3/4 attempts to > do) and then leave p->state==NULL, indicating that no state is actively > selected. IIRC, this would be the same as right after the initial > pinctrl_select(). > > I wonder if it's likely that attempting to re-apply the old state would > actually work, given that applying something just failed. > > Finally, this recovery code doesn't: > > a) Process anything except MUX_GROUP; any pin config settings in the old > state aren't restored. > > b) (I think) Apply any mux settings that don't involve groups that are > referenced by both the old and new states; given that patch 3/4 attempts > to undo everything in the failed application of the new state, I think > this "re-apply the old state" code should simple run through everything > in the old state any apply it unconditionally. So, if I understand correctly, it could be as simple as that: } - if (old_state) { - list_for_each_entry(setting, &old_state->settings, node) { - bool found = false; - if (setting->type != PIN_MAP_TYPE_MUX_GROUP) - continue; - list_for_each_entry(setting2, &state->settings, node) { - if (setting2->type != PIN_MAP_TYPE_MUX_GROUP) - continue; - if (setting2->data.mux.group == - setting->data.mux.group) { - found = true; - break; - } - } - if (!found) - pinmux_enable_setting(setting); - } - } - p->state = old_state; + + if (old_state) + pinctrl_select_state_locked(p, NULL); + return ret; } > > c) Set p->state = oldstate, so it's left at NULL, which would confuse > any future pinctrl_select().