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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 7FD4CC432C3 for ; Tue, 3 Dec 2019 15:20:46 +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 514A2206EC for ; Tue, 3 Dec 2019 15:20:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="lV6bM3jG"; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="AWHhNjjj" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 514A2206EC Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mediatek-bounces+linux-mediatek=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:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+7LUODp3EoKkVwYMt2wTZ5CpAQkFTnrw1tuw9pCfbzA=; b=lV6bM3jGzwBeaN 25UrMxnlPneOeOe4Tr5xBPBseXDry0kFyVbbzjF/vYTlhE0orvxYjQnBYY5U6Voa6+zMF0Bnz6K+w HCAgHC8TQXvJIDVZ6JHX4hseztUk/ZDKMzWOjC/boF9V6UErkvwlFqOMnij8xLT7srvF6XLNqFrsX KTDb1cP3pahQw3H7cpzou9lgBvcqUpk4WnqaKRMbDUg6g9wTJO/EsSntvMrwM6eCRPZWojyg4winy h99YkfMLI824VmvcP5/9QVwPw1wzAXoILIGXVW2pxGdBwa7mD8T8QHcl4QvIkihDv+2whIhdTyO75 ITcQVRMurkJikBevTDhg==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1ic9ym-0004f8-Qo; Tue, 03 Dec 2019 15:20:44 +0000 Received: from mail-lj1-x242.google.com ([2a00:1450:4864:20::242]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ic9yg-0004VT-Gu for linux-mediatek@lists.infradead.org; Tue, 03 Dec 2019 15:20:40 +0000 Received: by mail-lj1-x242.google.com with SMTP id s22so4269123ljs.7 for ; Tue, 03 Dec 2019 07:20:38 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=m3zQ0bKSvISFi+1fBMi3jNVJYg+1MoT8ThtuF+2ovSQ=; b=AWHhNjjjjGYoZzrFZIUydXTE8P04GoVEj/nkxXov5Xl+m6KVTmezfYzIS189Xbp2d9 AoBT8kGo9Ilce7YjmHJ3BR2nLuZhHz+3UDJ/UUeou1iPTqwGwNddK1xb8tuMlXbwtqUv IvCc9hkMqkDp2pZ1+fqZfUoFvFdi6r9t/BjcweQbftCQDIBBsX3LPi/p1NolQb2re4oG PcRRUdNQdc96SBz0HlnkEujZ0AHARIftTj2fcd6E527NVp6lJFODir0h6yiz4ltMi1q/ ex1vgLswTSItO9QwCbjS0LEF/qs2+n2yDsn1fJAg1JwWMO95Ffh1DJlmg/hRr4/s9Iog mqEg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=m3zQ0bKSvISFi+1fBMi3jNVJYg+1MoT8ThtuF+2ovSQ=; b=qsXntaM89PeA7VDjX78ZAIMyG4lGdtLd+Aoi/YIxpD1lLLOKwnjkUtHgyLFR5SrLot 1hfob7H5j0pCwjmgJ4dzjmZw84xnRMPmV9YJ8DsrMQ7Nt1LZkDb0T4K8OWWCKC1Fm+C6 gYcvhs2lUJCAPo2Ejwo++gCEsQYDi8nChsGEoon4IA0lZYW6hBAyGDGPicQlk76NuqRV GcSdfbyqCFiw1Zqh96C0RAn8W3PDHXYPREZCvlf1rf+kM1cZ3VF9zVnIoyNRIUWiUfGT gP7S1jWUfujVMC9N48HbMxi6u9uH1coogxqdfUSuHkwb5jI8fQmNc/vpjQ7hAXQ5ct54 OtqQ== X-Gm-Message-State: APjAAAX8nMB2BGQtuhpTkkaJ2tuiJ0/8oW3p690vzfvk3lQ4UzlS4v+A oXSvEui9cX28RHEg+1bTHQL19kuNZBiuvT4zKPv8Fg== X-Google-Smtp-Source: APXvYqzeswPvfb4bN8LEsJSRL/PyxST5l5bJCtG71jQQSWLOGmPl2rs5haGp6u2c8kSn123mUXgOro1vUhgVEbncNNQ= X-Received: by 2002:a2e:9ec4:: with SMTP id h4mr2954959ljk.77.1575386436713; Tue, 03 Dec 2019 07:20:36 -0800 (PST) MIME-Version: 1.0 References: <20191202193230.21310-1-sam@ravnborg.org> <20191202193230.21310-8-sam@ravnborg.org> <20191203074659.ilsyv4yx7pzw5vax@gilmour.lan> In-Reply-To: <20191203074659.ilsyv4yx7pzw5vax@gilmour.lan> From: Linus Walleij Date: Tue, 3 Dec 2019 16:20:24 +0100 Message-ID: Subject: Re: [PATCH v1 07/26] drm/panel: remove get_timings To: Maxime Ripard X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191203_072038_602615_423C0F87 X-CRM114-Status: GOOD ( 15.85 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Neil Armstrong , David Airlie , "open list:DRM PANEL DRIVERS" , Andrzej Hajda , Thierry Reding , Laurent Pinchart , Benjamin Gaignard , Sam Ravnborg , linux-samsung-soc , "open list:ARM/Rockchip SoC..." , Tomi Valkeinen , NXP Linux Team , Jagan Teki , Jitao Shi , Pengutronix Kernel Team , Maarten Lankhorst , Abhinav Kumar , "moderated list:ARM/Mediatek SoC support" , Stefan Agner , linux-tegra@vger.kernel.org, Sean Paul , Linux ARM , Purism Kernel Team , Linux-Renesas , Boris Brezillon , Daniel Vetter Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Hi Maxime, On Tue, Dec 3, 2019 at 8:47 AM Maxime Ripard wrote: > Using only the mode as we do currently has a bunch of shortcomings as > almost no encoder will be able to provide the typical pixel clock, and > that situation leads to multiple things: > > - If someone working on one encoder wants to upstream a panel they > have tested, chances are this will not be the typical pixel clock > / timings being used but rather the one that will match what that > SoC is capable of. Trouble comes when a second user comes in with > a different encoder and different capabilities, and then we have a > maintainance fight over which timing is the true timing (with a > significant chance that none of them are). > > - If we can't match the pixel clock, we currently have no easy way > to make the usual measures of reducing / growing the porches and > blankings areas to match the pixel clock we can provide, since we > don't have an easy way to get the tolerance on those timings for a > given panel. There's some ad hoc solutions on some drivers (I > think vc4 has that?) to ignore the panel and just play around with > the timings, but I think this should be generalised. I've been confused with these things as they look today and it seems the whole struct drm_display_mode could need some improvement? If .clock is supposed to be htotal * vtotal * vrefresh, what is the .clock doing there anyway. Sadly I am too inexperienced to realize where the tolerances should be stated, but I guess just stating that hsync_start etc are typical, then specify some tolerance for each would help a bit? On the DSI displays in video mode there is also this EOL area which seems to be where the logic is normally just idling for a while, that can be adjusted on some hardware as well, but I don't quite understand it admittedly. Sometimes I wonder if anyone really understands DSI... :/ Yours, Linus Walleij _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek