Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965251AbdLRQdX (ORCPT ); Mon, 18 Dec 2017 11:33:23 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:44678 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935729AbdLRQQO (ORCPT ); Mon, 18 Dec 2017 11:16:14 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Egil Hjelmeland , Andrew Lunn , "David S. Miller" , Sasha Levin Subject: [PATCH 4.14 125/178] net: dsa: lan9303: Do not disable switch fabric port 0 at .probe Date: Mon, 18 Dec 2017 16:49:21 +0100 Message-Id: <20171218152926.004793580@linuxfoundation.org> X-Mailer: git-send-email 2.15.1 In-Reply-To: <20171218152920.567991776@linuxfoundation.org> References: <20171218152920.567991776@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1767 Lines: 50 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Egil Hjelmeland [ Upstream commit 3c91b0c1de8d013490bbc41ce9ee8810ea5baddd ] Make the LAN9303 work when lan9303_probe() is called twice. For some unknown reason the LAN9303 switch fail to forward data when switch fabric port 0 TX is disabled during probe. (Write of LAN9303_MAC_TX_CFG_0 in lan9303_disable_processing_port().) In that situation the switch fabric seem to receive frames, because the ALR is learning addresses. But no frames are transmitted on any of the ports. In our system lan9303_probe() is called twice, first time dsa_register_switch() return -EPROBE_DEFER. As an experiment, modified the code to skip writing LAN9303_MAC_TX_CFG_0, port 0 during the first probe. Then the switch works as expected. Resolve the problem by not calling lan9303_disable_processing_port() on port 0 during probe. Ports 1 and 2 are still disabled. Although unsatisfying that the exact failure mechanism is not known, the patch should not cause any harm. Signed-off-by: Egil Hjelmeland Reviewed-by: Andrew Lunn Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/net/dsa/lan9303-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/net/dsa/lan9303-core.c +++ b/drivers/net/dsa/lan9303-core.c @@ -569,7 +569,7 @@ static int lan9303_disable_processing(st { int p; - for (p = 0; p < LAN9303_NUM_PORTS; p++) { + for (p = 1; p < LAN9303_NUM_PORTS; p++) { int ret = lan9303_disable_processing_port(chip, p); if (ret)