From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9EBFC433E0 for ; Thu, 28 May 2020 13:58:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5D0F20814 for ; Thu, 28 May 2020 13:58:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="0FISDt0i" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390604AbgE1N6d (ORCPT ); Thu, 28 May 2020 09:58:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37204 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390569AbgE1N6c (ORCPT ); Thu, 28 May 2020 09:58:32 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:3201:214:fdff:fe10:1be6]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 53AD6C05BD1E; Thu, 28 May 2020 06:58:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=FR6rpUTDy6YkCkRcXhb1NZpZMquu6OHks1/TSntn5g8=; b=0FISDt0iywTeivhDGysA/zkgE nTZuqcGb0OeYxSpAkY8KjuTh+iYDw8FNu2qxnIPR1H0s5XuPX+TuV7ubJYjdTh5nfdmylkfihePRc oHXIAaXsrGKymN14NAX3l4c+FFo76k4pktkmRpWeg9wa4Psy2EbWleD4SnMx9L7O1mRaENI/YI4G9 ZL2gjrYCRdNfgicuMARIrOwDAXMWXI6OE55kc1efIJ8y7metKX27qMoPbh8Pi82QjvScNVOwSZVBu n17EM1j7xmIZUUDkt/T4e+LAABaL3klLcotDxI4jtgYxb3+KPWXqzdpyrGP3+B2jICVimdiLI9LhM Kx8X+ic1g==; Received: from shell.armlinux.org.uk ([2001:4d48:ad52:3201:5054:ff:fe00:4ec]:46204) by pandora.armlinux.org.uk with esmtpsa (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jeJ3C-0005VB-Kn; Thu, 28 May 2020 14:58:26 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jeJ3B-0007Ww-I5; Thu, 28 May 2020 14:58:25 +0100 Date: Thu, 28 May 2020 14:58:25 +0100 From: Russell King - ARM Linux admin To: Linus Walleij Cc: "open list:GPIO SUBSYSTEM" , Bartosz Golaszewski , Hans Verkuil , stable Subject: Re: [PATCH] gpio: fix locking open drain IRQ lines Message-ID: <20200528135825.GV1551@shell.armlinux.org.uk> References: <20200527140758.162280-1-linus.walleij@linaro.org> <20200527141807.GQ1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Thu, May 28, 2020 at 03:46:04PM +0200, Linus Walleij wrote: > On Wed, May 27, 2020 at 4:18 PM Russell King - ARM Linux admin > wrote: > > On Wed, May 27, 2020 at 04:07:58PM +0200, Linus Walleij wrote: > > > > We provided the right semantics on open drain lines being > > > by definition output but incidentally the irq set up function > > > would only allow IRQs on lines that were "not output". > > > > > > Fix the semantics to allow output open drain lines to be used > > > for IRQs. > > > > > > Reported-by: Hans Verkuil > > > Cc: Russell King > > > Cc: stable@vger.kernel.org > > > Fixes: 256efaea1fdc ("gpiolib: fix up emulated open drain outputs") > > > > As I've pointed out in the reporting thread, I don't think it can be > > justified as a regression - it's a bug in its own right that has been > > discovered by unifying the gpiolib semantics, since the cec-gpio code > > will fail on hardware that can provide real open-drain outputs > > irrespective of that commit. > > > > So, you're really fixing a deeper problem that was never discovered > > until gpiolib's semantics were fixed to be more uniform. > > You're right, I was thinking of Fixes: as more of a mechanical > instruction to the stable kernel maintainers administrative machinery. > > I will use the other way to signal to stable where to apply this. I think it makes sense to apply this patch to stable kernels prior to the commit mentioned in the Fixes tag - but how far back is a good question. Certainly to the point that we ended up with code relying on this behaviour (so when cec-gpio was introduced?) -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTC for 0.8m (est. 1762m) line in suburbia: sync at 13.1Mbps down 424kbps up