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 F1908E71094 for ; Thu, 21 Sep 2023 16:56:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229599AbjIUQ4p (ORCPT ); Thu, 21 Sep 2023 12:56:45 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50146 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229564AbjIUQ4m (ORCPT ); Thu, 21 Sep 2023 12:56:42 -0400 Received: from mgamail.intel.com (mgamail.intel.com [192.55.52.151]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 62000AC for ; Thu, 21 Sep 2023 09:56:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695315385; x=1726851385; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=oay5k/k4FowXctAo6RDPN3Ut0nEsXm0SCNAvWbRxE3Q=; b=g3k6jL0zql5bqcpuSupFQwg/WHNONOsHE1HKTxQXWmZpxauFJ8E0fA7V 3bE0wz0r9RS+XoutOYDEHMo1Uc3mRRGk/UtDio2kAsoss4HEuajS7FqTG PhDOKy6s+LFbvmr7jNfsV2JRpJH/tNdvb9w9sIayrWtmS+kGm2K9S8Von nORuRcYkltq7XOSZ+qXcS6etHYLLw3YHvMWU6FlDH+vj9cJ7/gMf5548G N1lOL7b8Gdh1pG/Bn70EUN56I9FTG2Qp76LnlSMC7YP56GTRKOz5HIPYf Jc5akx5ppve2oUZS3z/J0OrpluDeQn7UKErsUsYjRYOewZzwuCZ4Gwe23 w==; X-IronPort-AV: E=McAfee;i="6600,9927,10839"; a="360747602" X-IronPort-AV: E=Sophos;i="6.03,165,1694761200"; d="scan'208";a="360747602" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Sep 2023 05:09:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10839"; a="1077875040" X-IronPort-AV: E=Sophos;i="6.03,165,1694761200"; d="scan'208";a="1077875040" Received: from jnikula-mobl4.fi.intel.com (HELO localhost) ([10.237.66.162]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Sep 2023 05:09:13 -0700 From: Jani Nikula To: Xin Ji , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , David Airlie , Daniel Vetter Cc: qwen@analogixsemi.com, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, hsinyi@chromium.org, bliang@analogixsemi.com, Xin Ji Subject: Re: [PATCH] drm/bridge: Add 200ms delay to wait FW HPD status stable In-Reply-To: <20230921091435.3524869-1-xji@analogixsemi.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20230921091435.3524869-1-xji@analogixsemi.com> Date: Thu, 21 Sep 2023 15:09:10 +0300 Message-ID: <87leczpw2h.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 21 Sep 2023, Xin Ji wrote: > For the none-interrupt design(sink device is panel, polling HPD > status when chip power on), anx7625 FW has more than 200ms HPD > de-bounce time in FW, for the safety to get HPD status, driver > better to wait 200ms before HPD detection after OS resume back. > > Signed-off-by: Xin Ji > --- > drivers/gpu/drm/bridge/analogix/anx7625.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c > index 51abe42c639e..833d6d50a03d 100644 > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c > @@ -1464,6 +1464,9 @@ static int _anx7625_hpd_polling(struct anx7625_data *ctx, > if (ctx->pdata.intp_irq) > return 0; > > + /* Delay 200ms for FW HPD de-bounce */ > + usleep_range(200000, 201000); If you need to sleep for 200 ms, maybe use msleep instead? BR, Jani. > + > ret = readx_poll_timeout(anx7625_read_hpd_status_p0, > ctx, val, > ((val & HPD_STATUS) || (val < 0)), -- Jani Nikula, Intel