From mboxrd@z Thu Jan 1 00:00:00 1970 From: Linus Walleij Subject: Re: Fw: [3.18.3] poll() on gpio pins broken Date: Mon, 9 Mar 2015 16:52:26 +0100 Message-ID: References: <20150130234552.GA20407@sysresccd> <20150131083300.GZ21469@belle.intranet.vanheusden.com> <20150203090325.GA29693@deathray> <20150219085303.GI21469@belle.intranet.vanheusden.com> <20150302072655.GA17089@deathray> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: Received: from mail-oi0-f45.google.com ([209.85.218.45]:46931 "EHLO mail-oi0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753769AbbCIPw0 (ORCPT ); Mon, 9 Mar 2015 11:52:26 -0400 Received: by oiav63 with SMTP id v63so30095358oia.13 for ; Mon, 09 Mar 2015 08:52:26 -0700 (PDT) In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Alexandre Courbot Cc: Michael Welling , folkert , "linux-gpio@vger.kernel.org" On Wed, Mar 4, 2015 at 1:43 PM, Alexandre Courbot wrote: > On Tue, Mar 3, 2015 at 7:31 PM, Linus Walleij wrote: >> On Tue, Mar 3, 2015 at 9:27 AM, Alexandre Courbot wrote: >> >>> It really comes down to how user-space wants to access GPIOs. I >>> suspect the majority of sysfs accesses is done by scripts and other >>> simple programs. If we introduce a char device that takes requires >>> ioctls, it is then customary to add a small user-space library to >>> abstract that (for both convenience and safety - think libdrm). Do we >>> want to maintain libgpio? >> >> Good point. >> >> We have no clue about how the majority out there use the GPIO >> sysfs, but I have heard of mission-critical systems just hammering >> GPIOs from userspace. >> >> Sadly many of these industrial users are "I just want it to work, now" >> types and they don't step forward much on these mailing lists. >> (Learned from private conversations...) >> >> Maybe if noone voice their opinion and offer to help with this, we can >> assume they don't exist (well obviously a community does not exist) >> and their specific needs be ignored until they put their money where >> their mouth is. > > That's the only way we can handle the situation if people don't > manifest their needs. But does this mean that you would agree with a > cleaner, multi-GPIO friendly sysfs-based solution, or I am > misunderstanding you? I guess I'm just a bit grumpy. Whoever comes up with a cleaner sysfs or a clean device interface will win the argument and lock the path for the other approach. It's like a forking path with no going back or something. Yours, Linus Walleij