From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757963AbcHCQHr (ORCPT ); Wed, 3 Aug 2016 12:07:47 -0400 Received: from mx2.suse.de ([195.135.220.15]:58059 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751501AbcHCQHp (ORCPT ); Wed, 3 Aug 2016 12:07:45 -0400 Date: Wed, 3 Aug 2016 18:03:34 +0200 From: "Luis R. Rodriguez" To: Dmitry Torokhov , Jeff Mahoney , Andrew Morton , Takashi Iwai Cc: "Luis R. Rodriguez" , Daniel Wagner , Arend van Spriel , Bjorn Andersson , Daniel Wagner , Bastien Nocera , Greg Kroah-Hartman , Johannes Berg , Kalle Valo , Ohad Ben-Cohen , Mimi Zohar , David Howells , Andy Lutomirski , David Woodhouse , Julia Lawall , "linux-input@vger.kernel.org" , linux-kselftest@vger.kernel.org, linux-wireless , lkml Subject: Re: [RFC v0 7/8] Input: ims-pcu: use firmware_stat instead of completion Message-ID: <20160803160334.GM3296@wotan.suse.de> References: <20160730165817.GQ3296@wotan.suse.de> <37a3cd66-262e-ffbe-ea7a-a6d5b1ca1c8b@bmw-carit.de> <20160801194408.GZ3296@wotan.suse.de> <0f9350fa-e8b5-9d64-b2d3-afda5e5f6bbf@bmw-carit.de> <20160802063419.GG3296@wotan.suse.de> <2713d779-ef55-793d-f37e-d1414bb1bfc2@bmw-carit.de> <20160802074106.GI3296@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 03, 2016 at 12:42:14AM -0700, Dmitry Torokhov wrote: > On Tue, Aug 2, 2016 at 12:41 AM, Luis R. Rodriguez wrote: > > On Tue, Aug 02, 2016 at 08:53:55AM +0200, Daniel Wagner wrote: > >> On 08/02/2016 08:34 AM, Luis R. Rodriguez wrote: > >> >On Tue, Aug 02, 2016 at 07:49:19AM +0200, Daniel Wagner wrote: > >> >>>The sysdata API's main goal rather is to provide a flexible API first, > >> >>>compartamentalizing the usermode helper was secondary. But now it seems > >> >>>I may just also add devm support too to help simplify code further. > >> >> > >> >>I missed the point that you plan to add usermode helper support to > >> >>the sysdata API. > >> > > >> >I had no such plans, when I have asked folks so far about "hey are you > >> >really in need for it, OK what for? " and "what extended uses do you > >> >envision?" so I far I have not gotten any replies at all. So -- instead > >> >sysdata currently ignores it. > >> > >> So you argue for the remoteproc use case with 100+ MB firmware that > >> if there is a way to load after pivot_root() (or other additional > >> firmware partition shows up) then there is no need at all for > >> usermode helper? > > > > No, I'm saying I'd like to hear valid uses cases for the usermode helper and so > > far I have only found using coccinelle grammar 2 explicit users, that's it. My > > patch series (not yet merge) then annotates these as valid as I've verified > > through their documentation they have some quirky requirement. > > In certain configurations (embedded) people do not want to use > initramfs nor modules nor embed firmware into the kernel. In this case > usermode helper + firmware calss timeout handling provides necessary > wait for the root filesystem to be mounted. > > If we solve waiting for rootfs (or something else that may contain > firmware) then these cases will not need to use usermode helper. Given most distributions already disable FW_LOADER_USER_HELPER_FALLBACK and grammar shows we only have 2 explicit users of the usermode helper I'd prefer if we indeed could just compartamentalize the usermode helper and not rely on it further. Furthermore I think its possible address this issue, and suggested at least one idea how for now. With a bit further review I'm in hope we can address this well, not only for the firmware API but for all other kernel_read_file*() users. Luis