Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752519AbbK1QoE (ORCPT ); Sat, 28 Nov 2015 11:44:04 -0500 Received: from vps0.lunn.ch ([178.209.37.122]:43509 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752071AbbK1Qn6 (ORCPT ); Sat, 28 Nov 2015 11:43:58 -0500 Date: Sat, 28 Nov 2015 17:43:37 +0100 From: Andrew Lunn To: Duan Andy Cc: Lothar Wa?mann , "David S. Miller" , Fabio Estevam , Kevin Hao , Lucas Stach , Philippe Reynes , Russell King , Uwe Kleine-K?nig , "linux-kernel@vger.kernel.org" , "netdev@vger.kernel.org" , Stefan Agner Subject: Re: [PATCH] net: fec: fix enet_out clock handling Message-ID: <20151128164337.GF32356@lunn.ch> References: <1448631550-943-1-git-send-email-LW@KARO-electronics.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 706 Lines: 16 > When MAC is not ready with clocks disabled, it is not necessary to > supply clock for PHY. In fact, PHY also is not ready, why does it > need clock ? How about the case of the "PHY" is actually a switch? You can use the MDIO bus separate from the MAC, you can configure the switch while the MAC is down, etc. Packets can be flowing in and out of switch ports, while the MAC is down. You only need the MAC up when the host wants to send packets. Andrew -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/