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=-8.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 B6C5AC43215 for ; Tue, 3 Dec 2019 08:18:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8C98D206DF for ; Tue, 3 Dec 2019 08:18:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="npbVtp4q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726521AbfLCISN (ORCPT ); Tue, 3 Dec 2019 03:18:13 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:59352 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725845AbfLCISN (ORCPT ); Tue, 3 Dec 2019 03:18:13 -0500 Received: from pendragon.ideasonboard.com (81-175-216-236.bb.dnainternet.fi [81.175.216.236]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id E0FEC309; Tue, 3 Dec 2019 09:18:09 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1575361090; bh=jWj05kR5wYrupjrk3T8+pen6tr588LJHj3LcaenLTzA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=npbVtp4q7zoyBlia/uuSsc2CFM8DP7lrbQZ3pr/jKboayvD4s/ufTfOUmgwJGJkFJ UdYBFDJyCu6pB6gK8cGfJa/veMnt5ai0Cd1G4DmwQj3iK4L3OXPV4RkOg8wGtuC/Im gSs9p6lunYZnoWaIzBS4ugcXSBqQ9ngY/W9OT+OY= Date: Tue, 3 Dec 2019 10:18:03 +0200 From: Laurent Pinchart To: Maxime Ripard Cc: Sam Ravnborg , dri-devel@lists.freedesktop.org, Thierry Reding , Abhinav Kumar , Andrzej Hajda , Benjamin Gaignard , Boris Brezillon , Daniel Vetter , David Airlie , Jagan Teki , Jitao Shi , Linus Walleij , linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-renesas-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-tegra@vger.kernel.org, Maarten Lankhorst , Neil Armstrong , NXP Linux Team , Pengutronix Kernel Team , Purism Kernel Team , Sean Paul , Stefan Agner , Tomi Valkeinen Subject: Re: [PATCH v1 07/26] drm/panel: remove get_timings Message-ID: <20191203081803.GA12294@pendragon.ideasonboard.com> References: <20191202193230.21310-1-sam@ravnborg.org> <20191202193230.21310-8-sam@ravnborg.org> <20191203074659.ilsyv4yx7pzw5vax@gilmour.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191203074659.ilsyv4yx7pzw5vax@gilmour.lan> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org Hi Maxime, On Tue, Dec 03, 2019 at 08:46:59AM +0100, Maxime Ripard wrote: > On Mon, Dec 02, 2019 at 08:32:11PM +0100, Sam Ravnborg wrote: > > There was no users - so remove it. > > The callback was implemented in two drivers - deleted. > > > > Signed-off-by: Sam Ravnborg > > Cc: Thierry Reding > > Cc: Laurent Pinchart > > Cc: Sam Ravnborg > > Cc: Maarten Lankhorst > > Cc: Maxime Ripard > > Cc: David Airlie > > Cc: Daniel Vetter > > --- > > drivers/gpu/drm/panel/panel-seiko-43wvf1g.c | 18 ------------------ > > drivers/gpu/drm/panel/panel-simple.c | 18 ------------------ > > include/drm/drm_panel.h | 9 --------- > > 3 files changed, 45 deletions(-) > > > > diff --git a/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c b/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c > > index b878930b17e4..3bcba64235c4 100644 > > --- a/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c > > +++ b/drivers/gpu/drm/panel/panel-seiko-43wvf1g.c > > @@ -217,30 +217,12 @@ static int seiko_panel_get_modes(struct drm_panel *panel, > > return seiko_panel_get_fixed_modes(p, connector); > > } > > > > -static int seiko_panel_get_timings(struct drm_panel *panel, > > - unsigned int num_timings, > > - struct display_timing *timings) > > -{ > > - struct seiko_panel *p = to_seiko_panel(panel); > > - unsigned int i; > > - > > - if (p->desc->num_timings < num_timings) > > - num_timings = p->desc->num_timings; > > - > > - if (timings) > > - for (i = 0; i < num_timings; i++) > > - timings[i] = p->desc->timings[i]; > > - > > - return p->desc->num_timings; > > -} > > - > > static const struct drm_panel_funcs seiko_panel_funcs = { > > .disable = seiko_panel_disable, > > .unprepare = seiko_panel_unprepare, > > .prepare = seiko_panel_prepare, > > .enable = seiko_panel_enable, > > .get_modes = seiko_panel_get_modes, > > - .get_timings = seiko_panel_get_timings, > > }; > > If anything, I think we should grow the usage of timings and / or make > it usable by everyone. > > 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. > > Timings solves the first case since we have the operating range now > and not a single set of timings, and it solves the second since we can > use that range to take those measures instead of taking a shot in the > dark. > > I appreciate that it's pretty far from where we are today, but > removing the get_timings means that all the timings already defined in > the panel drivers are becoming useless too, and that eventually it > will get removed. I agree with you. -- Regards, Laurent Pinchart