From patchwork Mon Jun 29 06:00:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chen-Yu Tsai X-Patchwork-Id: 11630429 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7739313B4 for ; Mon, 29 Jun 2020 06:00:53 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 54D7723130 for ; Mon, 29 Jun 2020 06:00:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="GRSZFxsR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54D7723130 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5CDB76E029; Mon, 29 Jun 2020 06:00:49 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by gabe.freedesktop.org (Postfix) with ESMTPS id 4F8306E029 for ; Mon, 29 Jun 2020 06:00:48 +0000 (UTC) Received: from wens.tw (mirror2.csie.ntu.edu.tw [140.112.194.72]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 720452312E; Mon, 29 Jun 2020 06:00:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1593410447; bh=69KAXq7nSrNne8dVE7YVsV2/lDTgQzzsUVum5KwNVZc=; h=From:To:Cc:Subject:Date:From; b=GRSZFxsRZTWvOaiuzo8KJuHhWg6fv0kcWT84LyI53REIlQNAFJBgWtSDfy0UeBZrb zDuzXx4213NUAaSuiH3mKzaSCcQNusd1UXAOiWVQZ6qcnUZF9DMNA9p/WftCz9AdGk 0cjZOAuZXSdbSxPfzzuRm+wEa09MV4SsfP8A07Dk= Received: by wens.tw (Postfix, from userid 1000) id 13E895FCA9; Mon, 29 Jun 2020 14:00:45 +0800 (CST) From: Chen-Yu Tsai To: Maxime Ripard , David Airlie , Daniel Vetter Subject: [PATCH] drm: sun4i: hdmi: Remove extra HPD polling Date: Mon, 29 Jun 2020 14:00:32 +0800 Message-Id: <20200629060032.24134-1-wens@kernel.org> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Chen-Yu Tsai , linux-arm-kernel@lists.infradead.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" From: Chen-Yu Tsai The HPD sense mechanism in Allwinner's old HDMI encoder hardware is more or less an input-only GPIO. Other GPIO-based HPD implementations directly return the current state, instead of polling for a specific state and returning the other if that times out. Remove the I/O polling from sun4i_hdmi_connector_detect() and directly return a known state based on the current reading. This also gets rid of excessive CPU usage by kworker as reported on Stack Exchange [1] and Armbian forums [2]. [1] https://superuser.com/questions/1515001/debian-10-buster-on-cubietruck-with-bug-in-sun4i-drm-hdmi [2] https://forum.armbian.com/topic/14282-headless-systems-and-sun4i_drm_hdmi-a10a20/ Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support") Signed-off-by: Chen-Yu Tsai --- drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c index ce07ddc3e058..557cbe5ab35f 100644 --- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c +++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c @@ -259,9 +259,8 @@ sun4i_hdmi_connector_detect(struct drm_connector *connector, bool force) struct sun4i_hdmi *hdmi = drm_connector_to_sun4i_hdmi(connector); unsigned long reg; - if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_HPD_REG, reg, - reg & SUN4I_HDMI_HPD_HIGH, - 0, 500000)) { + reg = readl(hdmi->base + SUN4I_HDMI_HPD_REG); + if (reg & SUN4I_HDMI_HPD_HIGH) { cec_phys_addr_invalidate(hdmi->cec_adap); return connector_status_disconnected; }