From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net/tg3: Avoid delay during MMIO access Date: Tue, 25 Jun 2013 17:01:25 -0700 (PDT) Message-ID: <20130625.170125.60596231117979470.davem@davemloft.net> References: <1372145072-8559-1-git-send-email-shangw@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, mcarlson@broadcom.com, benh@kernel.crashing.org To: shangw@linux.vnet.ibm.com Return-path: Received: from shards.monkeyblade.net ([149.20.54.216]:35323 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751586Ab3FZAB0 (ORCPT ); Tue, 25 Jun 2013 20:01:26 -0400 In-Reply-To: <1372145072-8559-1-git-send-email-shangw@linux.vnet.ibm.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Gavin Shan Date: Tue, 25 Jun 2013 15:24:32 +0800 > When the EEH error is the result of a fenced host bridge, MMIO accesses > can be very slow (milliseconds) to timeout and return all 1's, > thus causing the driver various timeout loops to take way too long and > trigger soft-lockup warnings (in addition to taking minutes to recover). > > It might be worthwhile to check if for any of these cases, ffffffff is > a valid possible value, and if not, bail early since that means the HW > is either gone or isolated. In the meantime, checking that the PCI channel > is offline would be workaround of the problem. > > Cc: # v3.0+ > Signed-off-by: Gavin Shan Applied and queued up for -stable, thanks.