From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net: phy: marvell: avoid pause mode on SGMII-to-Copper for 88e151x Date: Mon, 18 Dec 2017 15:04:56 -0500 (EST) Message-ID: <20171218.150456.625421280463615366.davem@davemloft.net> References: Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: andrew@lunn.ch, f.fainelli@gmail.com, netdev@vger.kernel.org To: rmk+kernel@armlinux.org.uk Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:40376 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756931AbdLRUFA (ORCPT ); Mon, 18 Dec 2017 15:05:00 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: From: Russell King Date: Fri, 15 Dec 2017 16:10:20 +0000 > Observed on the 88e1512 in SGMII-to-Copper mode, negotiating pause > is unreliable. While the pause bits can be set in the advertisment > register, they clear shortly after negotiation with a link partner > commences irrespective of the cause of the negotiation. > > While these bits may be correctly conveyed to the link partner on the > first negotiation, a subsequent negotiation (eg, due to negotiation > restart by the link partner, or reconnection of the cable) will result > in the link partner seeing these bits as zero, while the kernel > believes that it has advertised pause modes. > > This leads to the local kernel evaluating (eg) symmetric pause mode, > while the remote end evaluates that we have no pause mode capability. > > Since we can't guarantee the advertisment, disable pause mode support > with this PHY when used in SGMII-to-Copper mode. > > The 88e1510 in RGMII-to-Copper mode appears to behave correctly. > > Reviewed-by: Andrew Lunn > Signed-off-by: Russell King Applied.