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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 1ic3O3-00047s-1y; Tue, 03 Dec 2019 08:18:23 +0000 Received: from perceval.ideasonboard.com ([2001:4b98:dc2:55:216:3eff:fef7:d647]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1ic3Nt-0003zR-4j; Tue, 03 Dec 2019 08:18:14 +0000 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 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-Disposition: inline In-Reply-To: <20191203074659.ilsyv4yx7pzw5vax@gilmour.lan> 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-20191203_001813_479468_F8435F5E X-CRM114-Status: GOOD ( 26.30 ) 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 , Linus Walleij , dri-devel@lists.freedesktop.org, Andrzej Hajda , Thierry Reding , Benjamin Gaignard , Sam Ravnborg , linux-samsung-soc@vger.kernel.org, linux-rockchip@lists.infradead.org, Tomi Valkeinen , NXP Linux Team , Jagan Teki , Jitao Shi , Pengutronix Kernel Team , Maarten Lankhorst , Abhinav Kumar , linux-mediatek@lists.infradead.org, Stefan Agner , linux-tegra@vger.kernel.org, Sean Paul , linux-arm-kernel@lists.infradead.org, Purism Kernel Team , linux-renesas-soc@vger.kernel.org, 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 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 _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek