From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3516D215766; Wed, 7 May 2025 18:48:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746643691; cv=none; b=EKI30lZMvqcWnyltRDnovAtrntrToI6VvQGP92vI3gMdKthfM+QEvFZfCvxjWdKrgqwlS1hkqhQ6zPhFm9EXi5P1Oy5fx9dS6CtQRO/xf88vTuQeig854LdSKW4ycQXOs/xtFshmW0IqTOE/6q7CpRaGQJc/eEfQsLhrEMgMtR4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746643691; c=relaxed/simple; bh=2AZJLiwHUhn2ou3gaWTK1/d/tJ684NDodbfOCOTMF8w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z65a39QQCLFMifNO80tPwkSiJBX/3BgsE2PqS5l5VoL+fI1nHf2vTwPy4LaIxuatv6I4I4sfTrbZuQkngyDmReOdZjcCBZLd1kulpg2E9P0AqWCP7uq+OdE+yPsKv2OUx3d+F1Yueijo9GYkugZ5lH6ga8NRqb3blsDrWADa2Gc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=OFUUxDKP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="OFUUxDKP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADF7DC4CEE2; Wed, 7 May 2025 18:48:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1746643691; bh=2AZJLiwHUhn2ou3gaWTK1/d/tJ684NDodbfOCOTMF8w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OFUUxDKPgSkjRfxoHbCN7IGczQtkHIJVgvUz+4riSzjx+UZAtLGZ8joLzz1ZzYMQ8 N/Hve2G500jCzUYAnj/vvLBsqc8qmVsHIjjMdib9FveDyYXwp4A+KNxxFWHQUpEPnT LP97XEE+5Ez5sCGjNKfQvApqnYBkRV/bYLUqLBKE= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fiona Klute , kernel-list@raspberrypi.com, Andrew Lunn , Paolo Abeni , Sasha Levin Subject: [PATCH 6.1 83/97] net: phy: microchip: force IRQ polling mode for lan88xx Date: Wed, 7 May 2025 20:39:58 +0200 Message-ID: <20250507183810.318613379@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250507183806.987408728@linuxfoundation.org> References: <20250507183806.987408728@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Fiona Klute [ Upstream commit 30a41ed32d3088cd0d682a13d7f30b23baed7e93 ] With lan88xx based devices the lan78xx driver can get stuck in an interrupt loop while bringing the device up, flooding the kernel log with messages like the following: lan78xx 2-3:1.0 enp1s0u3: kevent 4 may have been dropped Removing interrupt support from the lan88xx PHY driver forces the driver to use polling instead, which avoids the problem. The issue has been observed with Raspberry Pi devices at least since 4.14 (see [1], bug report for their downstream kernel), as well as with Nvidia devices [2] in 2020, where disabling interrupts was the vendor-suggested workaround (together with the claim that phylib changes in 4.9 made the interrupt handling in lan78xx incompatible). Iperf reports well over 900Mbits/sec per direction with client in --dualtest mode, so there does not seem to be a significant impact on throughput (lan88xx device connected via switch to the peer). [1] https://github.com/raspberrypi/linux/issues/2447 [2] https://forums.developer.nvidia.com/t/jetson-xavier-and-lan7800-problem/142134/11 Link: https://lore.kernel.org/0901d90d-3f20-4a10-b680-9c978e04ddda@lunn.ch Fixes: 792aec47d59d ("add microchip LAN88xx phy driver") Signed-off-by: Fiona Klute Cc: kernel-list@raspberrypi.com Cc: stable@vger.kernel.org Reviewed-by: Andrew Lunn Link: https://patch.msgid.link/20250416102413.30654-1-fiona.klute@gmx.de Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- drivers/net/phy/microchip.c | 46 +++---------------------------------- 1 file changed, 3 insertions(+), 43 deletions(-) diff --git a/drivers/net/phy/microchip.c b/drivers/net/phy/microchip.c index 0b88635f4fbca..623607fd2cefd 100644 --- a/drivers/net/phy/microchip.c +++ b/drivers/net/phy/microchip.c @@ -31,47 +31,6 @@ static int lan88xx_write_page(struct phy_device *phydev, int page) return __phy_write(phydev, LAN88XX_EXT_PAGE_ACCESS, page); } -static int lan88xx_phy_config_intr(struct phy_device *phydev) -{ - int rc; - - if (phydev->interrupts == PHY_INTERRUPT_ENABLED) { - /* unmask all source and clear them before enable */ - rc = phy_write(phydev, LAN88XX_INT_MASK, 0x7FFF); - rc = phy_read(phydev, LAN88XX_INT_STS); - rc = phy_write(phydev, LAN88XX_INT_MASK, - LAN88XX_INT_MASK_MDINTPIN_EN_ | - LAN88XX_INT_MASK_LINK_CHANGE_); - } else { - rc = phy_write(phydev, LAN88XX_INT_MASK, 0); - if (rc) - return rc; - - /* Ack interrupts after they have been disabled */ - rc = phy_read(phydev, LAN88XX_INT_STS); - } - - return rc < 0 ? rc : 0; -} - -static irqreturn_t lan88xx_handle_interrupt(struct phy_device *phydev) -{ - int irq_status; - - irq_status = phy_read(phydev, LAN88XX_INT_STS); - if (irq_status < 0) { - phy_error(phydev); - return IRQ_NONE; - } - - if (!(irq_status & LAN88XX_INT_STS_LINK_CHANGE_)) - return IRQ_NONE; - - phy_trigger_machine(phydev); - - return IRQ_HANDLED; -} - static int lan88xx_suspend(struct phy_device *phydev) { struct lan88xx_priv *priv = phydev->priv; @@ -392,8 +351,9 @@ static struct phy_driver microchip_phy_driver[] = { .config_aneg = lan88xx_config_aneg, .link_change_notify = lan88xx_link_change_notify, - .config_intr = lan88xx_phy_config_intr, - .handle_interrupt = lan88xx_handle_interrupt, + /* Interrupt handling is broken, do not define related + * functions to force polling. + */ .suspend = lan88xx_suspend, .resume = genphy_resume, -- 2.39.5