From patchwork Mon Jun 27 12:47:15 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lucas Stach X-Patchwork-Id: 12896616 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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 27392C43334 for ; Mon, 27 Jun 2022 12:47:26 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 370E4112CBF; Mon, 27 Jun 2022 12:47:25 +0000 (UTC) Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by gabe.freedesktop.org (Postfix) with ESMTPS id 3A0531136B1 for ; Mon, 27 Jun 2022 12:47:23 +0000 (UTC) Received: from dude02.red.stw.pengutronix.de ([2a0a:edc0:0:1101:1d::28]) by metis.ext.pengutronix.de with esmtp (Exim 4.92) (envelope-from ) id 1o5o98-0002Gh-2H; Mon, 27 Jun 2022 14:47:18 +0200 From: Lucas Stach To: Neil Armstrong , Andrzej Hajda , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec Subject: [PATCH] drm: bridge: dw_hdmi: only trigger hotplug event on real link state change Date: Mon, 27 Jun 2022 14:47:15 +0200 Message-Id: <20220627124715.408258-1-l.stach@pengutronix.de> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 2a0a:edc0:0:1101:1d::28 X-SA-Exim-Mail-From: l.stach@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: dri-devel@lists.freedesktop.org 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: kernel@pengutronix.de, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" There are two events that signal a real change of the link state: HPD going high means the sink is newly connected or wants the source to re-read the EDID, RX sense going low is a indication that the link has been disconnected. Ignore the other two events that also trigger interrupts, but don't need immediate attention: HPD going low does not necessarily mean the link has been lost and should not trigger a immediate read of the status. RX sense going high also does not require a detect cycle, as HPD going high is the right point in time to read the EDID. Ignoring the negative HPD edge does make the detection much more robust against spurious link status changes due to EMI or marginal signal levels. Signed-off-by: Lucas Stach Reviewed-by: Neil Armstrong Signed-off-by: Lucas Stach --- drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c index 3e1be9894ed1..24f991b5248d 100644 --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c @@ -3095,6 +3095,7 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) { struct dw_hdmi *hdmi = dev_id; u8 intr_stat, phy_int_pol, phy_pol_mask, phy_stat; + enum drm_connector_status status = connector_status_unknown; intr_stat = hdmi_readb(hdmi, HDMI_IH_PHY_STAT0); phy_int_pol = hdmi_readb(hdmi, HDMI_PHY_POL0); @@ -3133,13 +3134,15 @@ static irqreturn_t dw_hdmi_irq(int irq, void *dev_id) cec_notifier_phys_addr_invalidate(hdmi->cec_notifier); mutex_unlock(&hdmi->cec_notifier_mutex); } - } - if (intr_stat & HDMI_IH_PHY_STAT0_HPD) { - enum drm_connector_status status = phy_int_pol & HDMI_PHY_HPD - ? connector_status_connected - : connector_status_disconnected; + if (phy_stat & HDMI_PHY_HPD) + status = connector_status_connected; + + if (!( phy_stat & HDMI_PHY_RX_SENSE)) + status = connector_status_disconnected; + } + if (status != connector_status_unknown) { dev_dbg(hdmi->dev, "EVENT=%s\n", status == connector_status_connected ? "plugin" : "plugout");