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=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 12E7FC48BD5 for ; Tue, 25 Jun 2019 14:08:07 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D1B40213F2 for ; Tue, 25 Jun 2019 14:08:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="DOVak4fR"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="DlsNVgfR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D1B40213F2 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ffwll.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=1OpFsgbIgeEAxDk1WH3YWOYdJ57ubm9TY2qFIRVadSo=; b=DOVak4fR8sOXug 0qGqlnK3yUGcljttWadLI6qJNQGpDZzOsNxhMiBflt3176T0Qh0fZV32eJaXFIHqumtaSqfCkyroq B4uwp2fCX2U72+oYdCBnm5tTjufnKi8SEJd4GJVdjvPomUtP/6DnWASmMRJWMPXZGPqrXBaFBpe3x TPPlS1PY1tSmx0UYuGv03WDOcLak0u+Rpl8A9ebnTQKW4NS63+WR+5hRlxAzYN5ivInuu6+AF0Yzr dYlUENh0SrTLDsTJoyxp/BxtHDmVYEwUDrfP+useDNlo2FU0raGy5cmWQwukVcSKrZfL3QNYlU2U0 Yp1WyA9M1htElJE1FvNw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1hfm7C-0000Q8-F7; Tue, 25 Jun 2019 14:08:06 +0000 Received: from mail-ed1-x541.google.com ([2a00:1450:4864:20::541]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1hfm76-0000Oz-IT for linux-arm-kernel@lists.infradead.org; Tue, 25 Jun 2019 14:08:02 +0000 Received: by mail-ed1-x541.google.com with SMTP id k8so27300409edr.11 for ; Tue, 25 Jun 2019 07:07:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=sender:date:from:to:cc:subject:message-id:mail-followup-to :references:mime-version:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=CAtg3PLJ+XKSV8dAF2QLAFWrkpUis1quRM8X3SddO/c=; b=DlsNVgfRWTP8NpGGrX9t3Nbz1zo7ltZhwtKOk/Es+ZdbHwht+lr3TCIe70hcYOlrBR ABPEEparLAqoeRRvZ5Pzq1cEVMTiKJ3tiqSO4M7ZzKp6aqKBOmxw686MYovwaEFXhy8l NK+f1Jf6pSuG3cXFg7wdY+FYcdimxOYB8sVXQ= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :mail-followup-to:references:mime-version:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=CAtg3PLJ+XKSV8dAF2QLAFWrkpUis1quRM8X3SddO/c=; b=IGHE8e2JIFXzL8BLRAug2AT93A5CjrLOoMPr+aI+xxgVXkpS8XK2Vugsae2KG3swrB InPpmtH9qACRKJjJEeFzviQkzr4YYyGvHFbJuN4YNqvh0N4vKRcjKgxQ7oQSDVYqt2+U 1dV8AWgtIAiz4L3vTJPZJQDa3v892IZ04kKyMJZEKUV0CGfyS3MlZ4ZsEH983L565lV1 I7v4HDjhMcD/CNRAv+S/f7PhCsEHSM0aPDzRMKGz8NBSdQ6SLOP1l8et0QInbrQZF6tT YDZw3SmjX3zYiGBTDQ69fl/Om/90aMqa4b3O0mtAMtVEPAEFu50yM0AGQOwcfaChk+Nm r/XA== X-Gm-Message-State: APjAAAW7+PLrMZbCtBHLAtmYKt09Xm/5kT3cD5KteR0jvyrW9viw4CLT rKiC6nySraVE+5SU1ZGiP0rtoQ== X-Google-Smtp-Source: APXvYqwnUNvO8RCgD+CoeE0AtlUeuwzv5wVl2MiDkEcmAY2cVmivLFNLtUKUMk2lZa5wxlyqXHk8gw== X-Received: by 2002:a50:92e1:: with SMTP id l30mr77999218eda.141.1561471678547; Tue, 25 Jun 2019 07:07:58 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:569e:0:3106:d637:d723:e855]) by smtp.gmail.com with ESMTPSA id w17sm4594091edi.15.2019.06.25.07.07.56 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 25 Jun 2019 07:07:57 -0700 (PDT) Date: Tue, 25 Jun 2019 16:07:55 +0200 From: Daniel Vetter To: Emil Velikov Subject: Re: [PATCH 0/2] Associate ddc adapters with connectors Message-ID: <20190625140755.GT12905@phenom.ffwll.local> Mail-Followup-To: Emil Velikov , Andrzej Pietrasiewicz , Russell King - ARM Linux admin , linux-samsung-soc@vger.kernel.org, Joonyoung Shim , Maxime Ripard , Seung-Woo Kim , Maarten Lankhorst , linux-kernel@vger.kernel.org, Krzysztof Kozlowski , Inki Dae , David Airlie , Kyungmin Park , Kukjin Kim , dri-devel@lists.freedesktop.org, kernel@collabora.com, Sean Paul , linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com References: <20190625100351.52ddptvb2gizaepi@shell.armlinux.org.uk> <817ccfba-754c-6a28-8d75-63f70605fd43@collabora.com> <20190625133639.GA16031@arch-x1c3> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20190625133639.GA16031@arch-x1c3> X-Operating-System: Linux phenom 4.19.0-5-amd64 User-Agent: Mutt/1.10.1 (2018-07-13) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190625_070800_665014_434A3978 X-CRM114-Status: GOOD ( 20.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Joonyoung Shim , Maxime Ripard , Maarten Lankhorst , Seung-Woo Kim , Russell King - ARM Linux admin , Krzysztof Kozlowski , Andrzej Pietrasiewicz , Inki Dae , David Airlie , Kyungmin Park , Kukjin Kim , dri-devel@lists.freedesktop.org, Daniel Vetter , kernel@collabora.com, Sean Paul , linux-kernel@vger.kernel.org, m.szyprowski@samsung.com Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jun 25, 2019 at 02:36:39PM +0100, Emil Velikov wrote: > On 2019/06/25, Andrzej Pietrasiewicz wrote: > > Hi Russell, > > = > > W dniu 25.06.2019 o=A012:03, Russell King - ARM Linux admin pisze: > > > On Tue, Jun 25, 2019 at 11:46:34AM +0200, Andrzej Pietrasiewicz wrote: > > > > It is difficult for a user to know which of the i2c adapters is for= which > > > > drm connector. This series addresses this problem. > > > > = > > > > The idea is to have a symbolic link in connector's sysfs directory,= e.g.: > > > > = > > > > ls -l /sys/class/drm/card0-HDMI-A-1/i2c-2 > > > > lrwxrwxrwx 1 root root 0 Jun 24 10:42 /sys/class/drm/card0-HDMI-A-1= /i2c-2 \ > > > > -> ../../../../soc/13880000.i2c/i2c-2 > > > = > > > Don't you want the symlink name to be "i2c" or something fixed, rather > > > than the name of the i2c adapter? Otherwise, you seem to be encumber= ing > > > userspace with searching the directory to try and find the symlink. > > > = > > = > > Thank you for your comment. So you imagine something on the lines of: > > = > > lrwxrwxrwx 1 root root 0 Jun 24 10:42 /sys/class/drm/card0-HDMI-A-1/ddc= \ > > -> ../../../../soc/13880000.i2c/i2c-2 > > = > > ? > > = > Fwiw my Intel machine lists a number of i2c devices: > /sys/class/drm/card0-DP-1/i2c-6 > /sys/class/drm/card0-DP-2/i2c-7 > /sys/class/drm/card0-eDP-1/i2c-5 > = > Note: I haven't looked _if_ they relate to ones you're proposing here. > = > One thing worth mentioning is, the ones I've seen are not symlinks to > another sysfs entries. And there aren't any i2c nodes in /dev ... > = > Just a random food for thought :-) Those are the i2c-over-dp-aux controllers. I think we want to list these too. Btw to make this more useful maybe some default implementations for get_modes which automatically dtrt, as a helper? Probably could use that to squash quite a bit of boilerplate. Otherwise I like this. Biggest problem I'm seeing here is rolling this out everywhere, this is a lot of work. And without widespread adoptions it's not terribly useful for userspace. -Daniel -- = Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel