From patchwork Mon Jun 20 11:04:50 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lukas Wunner X-Patchwork-Id: 12887388 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 12018C433EF for ; Mon, 20 Jun 2022 11:14:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241786AbiFTLOd (ORCPT ); Mon, 20 Jun 2022 07:14:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241785AbiFTLOT (ORCPT ); Mon, 20 Jun 2022 07:14:19 -0400 X-Greylist: delayed 479 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Mon, 20 Jun 2022 04:13:05 PDT Received: from mailout3.hostsharing.net (mailout3.hostsharing.net [IPv6:2a01:4f8:150:2161:1:b009:f236:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D340915FDA for ; Mon, 20 Jun 2022 04:13:05 -0700 (PDT) Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS DV RSA Mixed SHA256 2020 CA-1" (verified OK)) by mailout3.hostsharing.net (Postfix) with ESMTPS id 6E4AD10029E11; Mon, 20 Jun 2022 13:05:01 +0200 (CEST) Received: from localhost (unknown [89.246.108.87]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by h08.hostsharing.net (Postfix) with ESMTPSA id 2CD1861975D7; Mon, 20 Jun 2022 13:05:01 +0200 (CEST) X-Mailbox-Line: From 439a3f3168c2f9d44b5fd9bb8d2b551711316be6 Mon Sep 17 00:00:00 2001 Message-Id: <439a3f3168c2f9d44b5fd9bb8d2b551711316be6.1655714438.git.lukas@wunner.de> From: Lukas Wunner Date: Mon, 20 Jun 2022 13:04:50 +0200 Subject: [PATCH net] net: phy: smsc: Disable Energy Detect Power-Down in interrupt mode To: "David S. Miller" , Jakub Kicinski , Paolo Abeni , Eric Dumazet Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org, Steve Glendinning , UNGLinuxDriver@microchip.com, Oliver Neukum , Andre Edich , Oleksij Rempel , Martyn Welch , Gabriel Hojda , Christoph Fritz , Lino Sanfilippo , Philipp Rosenberger , Simon Han , Heiner Kallweit , Andrew Lunn , Russell King , Ferry Toth , Marek Szyprowski , Krzysztof Kozlowski , linux-samsung-soc@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org Simon reports that if two LAN9514 USB adapters are directly connected without an intermediate switch, the link fails to come up and link LEDs remain dark. The issue was introduced by commit 1ce8b37241ed ("usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling"). The PHY suffers from a known erratum wherein link detection becomes unreliable if Energy Detect Power-Down is used. In poll mode, the driver works around the erratum by briefly disabling EDPD for 640 msec to detect a neighbor, then re-enabling it to save power. In interrupt mode, no interrupt is signaled if EDPD is used by both link partners, so it must not be enabled at all. We'll recoup the power savings by enabling SUSPEND1 mode on affected LAN95xx chips in a forthcoming commit. Fixes: 1ce8b37241ed ("usbnet: smsc95xx: Forward PHY interrupts to PHY driver to avoid polling") Reported-by: Simon Han Signed-off-by: Lukas Wunner --- drivers/net/phy/smsc.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/smsc.c b/drivers/net/phy/smsc.c index 1b54684b68a0..96d3c40932d8 100644 --- a/drivers/net/phy/smsc.c +++ b/drivers/net/phy/smsc.c @@ -110,7 +110,7 @@ static int smsc_phy_config_init(struct phy_device *phydev) struct smsc_phy_priv *priv = phydev->priv; int rc; - if (!priv->energy_enable) + if (!priv->energy_enable || phydev->irq != PHY_POLL) return 0; rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS); @@ -210,6 +210,8 @@ static int lan95xx_config_aneg_ext(struct phy_device *phydev) * response on link pulses to detect presence of plugged Ethernet cable. * The Energy Detect Power-Down mode is enabled again in the end of procedure to * save approximately 220 mW of power if cable is unplugged. + * The workaround is only applicable to poll mode. Energy Detect Power-Down may + * not be used in interrupt mode lest link change detection becomes unreliable. */ static int lan87xx_read_status(struct phy_device *phydev) { @@ -217,7 +219,7 @@ static int lan87xx_read_status(struct phy_device *phydev) int err = genphy_read_status(phydev); - if (!phydev->link && priv->energy_enable) { + if (!phydev->link && priv->energy_enable && phydev->irq == PHY_POLL) { /* Disable EDPD to wake up PHY */ int rc = phy_read(phydev, MII_LAN83C185_CTRL_STATUS); if (rc < 0)