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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 012C7C04AB5 for ; Thu, 6 Jun 2019 09:30:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4C0A20684 for ; Thu, 6 Jun 2019 09:30:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727540AbfFFJaD (ORCPT ); Thu, 6 Jun 2019 05:30:03 -0400 Received: from asavdk4.altibox.net ([109.247.116.15]:54620 "EHLO asavdk4.altibox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727509AbfFFJaD (ORCPT ); Thu, 6 Jun 2019 05:30:03 -0400 Received: from ravnborg.org (unknown [158.248.194.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by asavdk4.altibox.net (Postfix) with ESMTPS id B7D1580522; Thu, 6 Jun 2019 11:30:00 +0200 (CEST) Date: Thu, 6 Jun 2019 11:29:59 +0200 From: Sam Ravnborg To: Laurent Pinchart Cc: linux-renesas-soc@vger.kernel.org, Laurent Pinchart , Jacopo Mondi , Kieran Bingham , dri-devel@lists.freedesktop.org Subject: Re: [PATCH v3 07/10] drm: rcar-du: Skip LVDS1 output on Gen3 when using dual-link LVDS mode Message-ID: <20190606092959.GB17442@ravnborg.org> References: <20190528141234.15425-1-laurent.pinchart+renesas@ideasonboard.com> <20190528141234.15425-8-laurent.pinchart+renesas@ideasonboard.com> <20190528164213.GB9610@ravnborg.org> <20190528165052.GB17874@pendragon.ideasonboard.com> <20190528170242.GB10262@ravnborg.org> <20190606075750.GE4931@pendragon.ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190606075750.GE4931@pendragon.ideasonboard.com> User-Agent: Mutt/1.10.1 (2018-07-13) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.3 cv=VcLZwmh9 c=1 sm=1 tr=0 a=UWs3HLbX/2nnQ3s7vZ42gw==:117 a=UWs3HLbX/2nnQ3s7vZ42gw==:17 a=jpOVt7BSZ2e4Z31A5e1TngXxSK0=:19 a=kj9zAlcOel0A:10 a=gi-eZXJGFL57LBb4nr0A:9 a=CjuIK1q_8ugA:10 Sender: linux-renesas-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-renesas-soc@vger.kernel.org Hi Laurent. > > > Gen3 is the newest generation :-) We thus use >= through the DU and LVDS > > > drivers to prepare for support of Gen4, just in case. > > > > OK, but I guess we agree that the comment needs a small update them. > > > > Actually I implicitly reads that it is only from Gen3 onwards that the > > LVDS1 encoder can be used as a companion. > > My initial understanding reading the comment was that this implmented a > > workaround for Gen3 - but it is a workarounf for missing features in > > older than Gen3. > > I wouldn't say workaround, it just makes sure that we don't try to > support LVDS dual-mode on older SoCs as the feature was added in Gen3 > hardware. > > > So, assuming this is correct, when trying to specify a companion on > > older then Gen3 should result in some kind of error/warning? > > (Maybe it does). > > The property is ignored in that case. I could add an error message, but > I'm not sure I should, as we don't usually check that DT nodes don't > contain any other property than the ones specified in the DT bindings > (an automatic DT runtime validator based on the YAML bindings could be > interesting ;-)). Again, thanks for taking your time. This clarifies it nicely. Sam