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=-6.8 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 DB212C04AB3 for ; Wed, 29 May 2019 05:57:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A52B720883 for ; Wed, 29 May 2019 05:57:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="ZS5kwl9p"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="ZS5kwl9p" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725879AbfE2F5S (ORCPT ); Wed, 29 May 2019 01:57:18 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:33968 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725874AbfE2F5R (ORCPT ); Wed, 29 May 2019 01:57:17 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id EE64D60795; Wed, 29 May 2019 05:57:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1559109436; bh=74Ne9sS3vTkaD1mJsi9vabiBu9b2KjBQaNeK5Xh8kGI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=ZS5kwl9p9omyxADk65Nf5iKFRGfND8XHq2UDHz8d59MZAecFVTIOFxcROO9Ig/jZq D6IRrGSMi0Uaylok6Ezt64S3YGWbE55OSyAu5Hu+miXQPWbR8MlYelIjaAQihMbu0y A7uopP5u5fDbL8ky7zDy9X1OJbMZjwfeb4GA52AM= Received: from [10.79.129.124] (blr-bdr-fw-01_globalnat_allzones-outside.qualcomm.com [103.229.18.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vivek.gautam@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id A66396029B; Wed, 29 May 2019 05:57:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1559109436; bh=74Ne9sS3vTkaD1mJsi9vabiBu9b2KjBQaNeK5Xh8kGI=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=ZS5kwl9p9omyxADk65Nf5iKFRGfND8XHq2UDHz8d59MZAecFVTIOFxcROO9Ig/jZq D6IRrGSMi0Uaylok6Ezt64S3YGWbE55OSyAu5Hu+miXQPWbR8MlYelIjaAQihMbu0y A7uopP5u5fDbL8ky7zDy9X1OJbMZjwfeb4GA52AM= DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org A66396029B Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=vivek.gautam@codeaurora.org Subject: Re: [PATCH 1/1] drm/panel: truly: Add additional delay after pulling down reset gpio To: Marc Gonzalez , airlied@linux.ie, thierry.reding@gmail.com, daniel@ffwll.ch Cc: Rob Clark , Bjorn Andersson , MSM , LKML References: <20190527102616.28315-1-vivek.gautam@codeaurora.org> <7dfcf294-6ab1-c1ce-352d-dfdeec4347af@free.fr> From: Vivek Gautam Message-ID: Date: Wed, 29 May 2019 11:27:10 +0530 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <7dfcf294-6ab1-c1ce-352d-dfdeec4347af@free.fr> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-arm-msm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 5/28/2019 2:13 PM, Marc Gonzalez wrote: > On 27/05/2019 12:26, Vivek Gautam wrote: > >> MTP SDM845 panel seems to need additional delay to bring panel >> to a workable state. Running modetest without this change displays >> blurry artifacts. >> >> Signed-off-by: Vivek Gautam >> --- >> drivers/gpu/drm/panel/panel-truly-nt35597.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/gpu/drm/panel/panel-truly-nt35597.c b/drivers/gpu/drm/panel/panel-truly-nt35597.c >> index fc2a66c53db4..aa7153fd3be4 100644 >> --- a/drivers/gpu/drm/panel/panel-truly-nt35597.c >> +++ b/drivers/gpu/drm/panel/panel-truly-nt35597.c >> @@ -280,6 +280,7 @@ static int truly_35597_power_on(struct truly_nt35597 *ctx) >> gpiod_set_value(ctx->reset_gpio, 1); >> usleep_range(10000, 20000); >> gpiod_set_value(ctx->reset_gpio, 0); >> + usleep_range(10000, 20000); > I'm not sure usleep_range() makes sense with these values. > > AFAIU, usleep_range() is typically used for sub-jiffy sleeps, and is based > on HRT to generate an interrupt. > > Once we get into jiffy granularity, it seems to me msleep() is good enough. > IIUC, it would piggy-back on the jiffy timer interrupt. > > In short, why not just use msleep(10); ? I am just maintaining the symmetry across older code. Thanks Vivek > > Regards.