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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 A878AC433E0 for ; Fri, 26 Jun 2020 13:35:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 83DA0207D8 for ; Fri, 26 Jun 2020 13:35:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ffwll.ch header.i=@ffwll.ch header.b="NJr3KisZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726770AbgFZNf5 (ORCPT ); Fri, 26 Jun 2020 09:35:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725864AbgFZNf4 (ORCPT ); Fri, 26 Jun 2020 09:35:56 -0400 Received: from mail-wm1-x344.google.com (mail-wm1-x344.google.com [IPv6:2a00:1450:4864:20::344]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A8EDEC03E979 for ; Fri, 26 Jun 2020 06:35:56 -0700 (PDT) Received: by mail-wm1-x344.google.com with SMTP id j18so8857082wmi.3 for ; Fri, 26 Jun 2020 06:35:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=DUYP0kDGls4xn6gexrnhT4lDqxkYAbZswvWk03qa/CY=; b=NJr3KisZ5ZL7jRavDurgiTgBAv8v6cNCm+jv8AmL1aIApQNSAwbXQWQDuIZZXf8Y2R BhDN0QmHNtsjqLwlD2U1uPOVQqJErK/zcOOyE5ZMNj96Cgdq2fzHfhTjF7kQ673t8mtz +XasLE7WO9HCuTMZv6Vbt9nz0krzKYtYxbANw= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=DUYP0kDGls4xn6gexrnhT4lDqxkYAbZswvWk03qa/CY=; b=Jq5+25K2EFgZ3G/gIj65K4T8py3lg4hUVY1rHDBY7g0mH3+BAn31vZpuL0cni9U5MX Yp+ncXBC4T0YyyXIpTP061g5Sjg/CkvSN/5IecY6N5PrhiOWHmXtXNIuzVTQyleU/8be qpdpMQQP0nx+zAqRNfY6fmVH8jZB0eXdmCqKCibx0lQGtINUS8Se3T6vDVWXY72hcd28 SINQ29xo/AWTtSgMdPE5LZLnhiLxMvZxk64X1tbhJA2ih2zL6AHVnTQ1GnJ9qcWW5T7T STW+1DL9Me6WBSF1/M1ZzsvuymhXLShwV/lpG+vMCz7de3yOLgB/MsFOyfzT6FejHyKF vFBw== X-Gm-Message-State: AOAM532vQlLMm0aWBOPvL6IiyHuinT3ZwObOQ1sgPAPWnMOW7PWMe/Km mQB4H52CCDsU0VhPHGunW0RloA== X-Google-Smtp-Source: ABdhPJwhtYRJxNF1kaTKX+aJCImOkd/+U+J7LhqpDarS02nXxdzfNK2GKqgdTbUm1HFYTCTk/QUgtQ== X-Received: by 2002:a1c:6887:: with SMTP id d129mr3462339wmc.179.1593178555417; Fri, 26 Jun 2020 06:35:55 -0700 (PDT) Received: from phenom.ffwll.local ([2a02:168:57f4:0:efd0:b9e5:5ae6:c2fa]) by smtp.gmail.com with ESMTPSA id x185sm5532952wmg.41.2020.06.26.06.35.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 26 Jun 2020 06:35:53 -0700 (PDT) Date: Fri, 26 Jun 2020 15:35:51 +0200 From: Daniel Vetter To: Daniel Stone Cc: Pekka Paalanen , Daniel Vetter , Jernej Skrabec , Laurent Pinchart , Jonas Karlman , Neil Armstrong , Kieran Bingham , Maling list - DRI developers , "open list:DRM DRIVERS FOR RENESAS" , Andrzej Hajda , Laurent Pinchart , Thomas Zimmermann , Sam Ravnborg Subject: Re: [PATCH 27/27] drm: Add default modes for connectors in unknown state Message-ID: <20200626133551.GD3278063@phenom.ffwll.local> References: <20200624072304.GT20149@phenom.ffwll.local> <20200625075655.GC3278063@phenom.ffwll.local> <20200625133157.0e749602@eldfell> <20200626115957.566efa5b@eldfell> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Operating-System: Linux phenom 5.6.0-1-amd64 Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org On Fri, Jun 26, 2020 at 10:25:45AM +0100, Daniel Stone wrote: > Hi, > > On Fri, 26 Jun 2020 at 10:00, Pekka Paalanen wrote: > > On Thu, 25 Jun 2020 12:44:36 +0200 Daniel Vetter wrote: > > > Maybe an aside, but the guideline is for autoconfiguration: > > > - Light up everything that has connector status connected. > > > - If nothing has that status, try to light up the connectors with > > > status "unknown". > > > > > > This is only really relevant on older platforms, mostly for VGA and > > > somewhat for dvi outputs. > > > > > > Maybe another thing we should put down somewhere in the uapi docs ... > > > > As I had no idea what "unknown" means or when it can happen, I assumed > > that it must mean "the hardware cannot know". If the hardware cannot > > know, then I certainly will not be trying to enable that, unless > > explicitly configured to do so. Having a phantom output is worse than > > having a real output that does not light up, because it's not obvious at > > first with phantom output that anything is wrong. You may just be > > wondering where your windows disappear, or where did you mouse cursor > > go, or why you see a wallpaper but no login dialog, etc. > > How about a refinement of Dan's suggestion, proceeding down this > logical order and breaking if true: > - ignore all disconnected outputs > - if any outputs are connected, ignore all unknown outputs > - if only one output is unknown, use only that output (with default > mode if need be) > - if any outputs are unknown but have EDID present, use only those outputs > - at this point, we have multiple unknown outputs with no EDID - break > and demand explicit user configuration EDID present generally means the status will be "connected". So not much of a refined. I'd say if you have multiple unknown, use a cloned config to avoid the "windows are disappearing" problem. Which is also what fbcon does, and iirc also -modesetting by default. But the most important part is to not light up "unknown" outputs if there's another output with a solid "connected". That avoids the problems Pekka points out, phantom outputs are bad. Really no need to refine beyond that, since imo that's a kernel bug. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch