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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 CF173C43613 for ; Thu, 20 Jun 2019 12:28:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AD1D8206E0 for ; Thu, 20 Jun 2019 12:28:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731670AbfFTM2X (ORCPT ); Thu, 20 Jun 2019 08:28:23 -0400 Received: from gloria.sntech.de ([185.11.138.130]:45944 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726294AbfFTM2W (ORCPT ); Thu, 20 Jun 2019 08:28:22 -0400 Received: from ip5f5a6320.dynamic.kabel-deutschland.de ([95.90.99.32] helo=diego.localnet) by gloria.sntech.de with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hdwAp-0003Td-BK; Thu, 20 Jun 2019 14:28:15 +0200 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Doug Anderson Cc: "open list:ARM/Rockchip SoC..." , Linux ARM , Yakir Yang , Matthias Kaehlcke , Enric Balletbo i Serra , LKML Subject: Re: [PATCH 04/10] ARM: dts: rockchip: add startup delay to rk3288-veyron panel-regulators Date: Thu, 20 Jun 2019 14:28:14 +0200 Message-ID: <2226970.BAPq4liE1j@diego> In-Reply-To: References: <1458265206-15733-1-git-send-email-heiko@sntech.de> <1458265206-15733-5-git-send-email-heiko@sntech.de> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Doug, Am Donnerstag, 20. Juni 2019, 03:27:55 CEST schrieb Doug Anderson: > On Wed, Fri, 18 Mar 2016 Heiko Stuebner wrote: > > > > The panels need a bit of time to actually turn on. If this isn't > > observed, this results in problems when trying talk to the panels > > and thus produces detection errors. 100ms seem to be a safe value > > for the time being. > > > > Signed-off-by: Heiko Stuebner > > --- > > arch/arm/boot/dts/rk3288-veyron-jaq.dts | 1 + > > arch/arm/boot/dts/rk3288-veyron-jerry.dts | 1 + > > arch/arm/boot/dts/rk3288-veyron-minnie.dts | 1 + > > arch/arm/boot/dts/rk3288-veyron-speedy.dts | 1 + > > 4 files changed, 4 insertions(+) > > I know it was 3 years ago, but any idea how to reproduce the problems > you were seeing without this patch? I believe the downstream kernel > never had any delay like this and I'm not aware of any issues. > > I wonder if the need for this extra 100 ms delay is no longer there > now that we have: > > 3157694d8c7f pwm-backlight: Add support for PWM delays proprieties. > 5fb5caee92ba pwm-backlight: Enable/disable the PWM before/after LCD > enable toggle. > 6d5922dd0d60 ARM: dts: rockchip: set PWM delay backlight settings for Veyron I just did a non-scientific test on my jerry+minnie and yes, simply reverting that patch does not seem to affect display bringup and I still get a prompt. So I guess we could just revert that patch in light of the changes. [patches welcome ;-) ] Heiko