From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Kirsher Subject: [net-next-2.6 PATCH 15/15] igb: add flushes between RAR writes when setting mac address Date: Mon, 05 Oct 2009 09:36:01 -0700 Message-ID: <20091005163601.32487.87871.stgit@localhost.localdomain> References: <20091005163058.32487.10125.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, gospo@redhat.com, Alexander Duyck , Jeff Kirsher To: davem@davemloft.net Return-path: Received: from qmta11.emeryville.ca.mail.comcast.net ([76.96.27.211]:45021 "EHLO QMTA11.emeryville.ca.mail.comcast.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753942AbZJEQiL (ORCPT ); Mon, 5 Oct 2009 12:38:11 -0400 In-Reply-To: <20091005163058.32487.10125.stgit@localhost.localdomain> Sender: netdev-owner@vger.kernel.org List-ID: From: Alexander Duyck There are some switches that will do write combining when they see two sequential regions written. In order to avoid any possible write combining issues it is necessary to add a flush after writing each piece of a rar register. Signed-off-by: Alexander Duyck Signed-off-by: Jeff Kirsher --- drivers/net/igb/e1000_mac.c | 7 +++++++ 1 files changed, 7 insertions(+), 0 deletions(-) diff --git a/drivers/net/igb/e1000_mac.c b/drivers/net/igb/e1000_mac.c index 4969a5b..2ad358a 100644 --- a/drivers/net/igb/e1000_mac.c +++ b/drivers/net/igb/e1000_mac.c @@ -247,8 +247,15 @@ void igb_rar_set(struct e1000_hw *hw, u8 *addr, u32 index) if (rar_low || rar_high) rar_high |= E1000_RAH_AV; + /* + * Some bridges will combine consecutive 32-bit writes into + * a single burst write, which will malfunction on some parts. + * The flushes avoid this. + */ wr32(E1000_RAL(index), rar_low); + wrfl(); wr32(E1000_RAH(index), rar_high); + wrfl(); } /**