From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751830Ab3C1Ri1 (ORCPT ); Thu, 28 Mar 2013 13:38:27 -0400 Received: from avon.wwwdotorg.org ([70.85.31.133]:40362 "EHLO avon.wwwdotorg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750993Ab3C1Ri0 (ORCPT ); Thu, 28 Mar 2013 13:38:26 -0400 Message-ID: <5154800F.1040007@wwwdotorg.org> Date: Thu, 28 Mar 2013 11:38:23 -0600 From: Stephen Warren User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: Richard GENOUD 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 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> <20130328173356.GA10420@lnx-rg> In-Reply-To: <20130328173356.GA10420@lnx-rg> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/28/2013 11:34 AM, Richard GENOUD wrote: > 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; I think you want to remove that line too, so that p->state == NULL in the error case, so that if the pinctrl_select_state_locked() call below also fails to restore the old state, then (!old_state) will be true inside the recursive call, so it doesn't recurse into itself forever. > + if (old_state) > + pinctrl_select_state_locked(p, NULL); You want to pass old_state rather than NULL there, I think.