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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9A467C001DE for ; Fri, 4 Aug 2023 08:19:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231657AbjHDITS (ORCPT ); Fri, 4 Aug 2023 04:19:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55628 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232559AbjHDITR (ORCPT ); Fri, 4 Aug 2023 04:19:17 -0400 Received: from relay3-d.mail.gandi.net (relay3-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::223]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60ECCAC for ; Fri, 4 Aug 2023 01:19:16 -0700 (PDT) Received: by mail.gandi.net (Postfix) with ESMTPSA id E795360005; Fri, 4 Aug 2023 08:19:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1691137155; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=XnHUETHA//S6zU6TjCZDIWn6kGObZLazw+SFJLVqfKw=; b=UaCx4BIndDrV5tluMsb/4ytu1W2UQEZoS74rLiIi0X+JB7+gCA4KaB5IfmSDwUY5zdiWqz dXyeLSd1jW69REGrjGUxMWTMYhQI3tmFVL3L4oPeE+E1HI4gevEE0vo9k0Tmei4pe/pP8k 1EJyn0C66tRUeDNQV7U76LitUKl572vZQqI1rsHv6vn2P15z462hXpHm+sOHPEv0agR8TA 1pOPcaEJKeo/mH6UtplUq6HI5PqoqIk4I3hNSLWSzMM5qSgny4XZ3gtk1mPhCqDYQUQLai Y0O1pVZmpr1yaJUDQqXDFgiel2KCjsu98Yvvq8RsAr20/QEgP8p6p51WJRUlfw== Date: Fri, 4 Aug 2023 10:19:12 +0200 From: Luca Ceresoli To: Marek Vasut Cc: Neil Armstrong , Conor Dooley , devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org, Rob Herring , Thierry Reding , Krzysztof Kozlowski , Sam Ravnborg Subject: Re: [PATCH 2/2] drm/panel-simple: Add Innolux G156HCE-L01 panel entry Message-ID: <20230804101912.696a02aa@booty> In-Reply-To: <01496199-5be9-7084-735d-55a11e30217f@denx.de> References: <20230731210258.256152-1-marex@denx.de> <20230731210258.256152-2-marex@denx.de> <20230803162314.122fab64@booty> <9b236561-36af-da7a-2caf-892be68e2b76@denx.de> <20230803170659.2e44e204@booty> <01496199-5be9-7084-735d-55a11e30217f@denx.de> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-GND-Sasl: luca.ceresoli@bootlin.com Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org Hi Marek, On Thu, 3 Aug 2023 19:10:35 +0200 Marek Vasut wrote: > On 8/3/23 17:06, Luca Ceresoli wrote: > > Hi Marek, > > > > On Thu, 3 Aug 2023 16:25:37 +0200 > > Marek Vasut wrote: > > > >> On 8/3/23 16:23, Luca Ceresoli wrote: > >>> Hi Marek, > >> > >> Hi, > >> > >>> On Mon, 31 Jul 2023 23:02:58 +0200 > >>> Marek Vasut wrote: > >>> > >>>> Add support for Innolux G156HCE-L01 15.6" 1920x1080 24bpp > >>>> dual-link LVDS TFT panel. Documentation is available at [1]. > >>> > >>> Interesting, I'm bringing up this exact panel right now and found your > >>> patch. > >>> > >>>> The middle frequency is tuned slightly upward from 70.93 MHz > >>>> to 72 MHz, otherwise the panel shows slight flicker. > >>> > >>> Using 70.93 MHz here does not show any flickering. I even tried going > >>> in the opposite direction and set 70 MHz, and to use different > >>> backlight settings, all without any flickering. > >>> > >>> Do you think you might be using a defective device? Would you have a > >>> chance of testing another sample? > >> > >> I have literally one such display. > >> > >> Which SoC do you use (and if applicable, which bridge) ? > > > > The panel is driven by the DSI-2 output of a i.MX8MP through a TI > > SN65DSI84 bridge. > > I use the LT9211 , so I wonder whether this might be another Lontium > specific oddity. Or maybe not. After checking the LVDS clock with an oscilloscope I discovered I was actually sending 77 MHz. After fixing it I found that my panel (of which I only have one sample as well) does not display any output with pixel clocks <= 75 MHz. It works with clocks >= 76 MHz. I'm trying to get more info about this. Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com