From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Horman Subject: Re: [RFC/PATCH v3] sh_eth: use RNC mode for packet reception Date: Wed, 4 Jun 2014 10:26:56 +0900 Message-ID: <20140604012656.GE25936@verge.net.au> References: <1401794473-30050-1-git-send-email-ben.dooks@codethink.co.uk> <538E685A.1000505@renesas.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Ben Dooks , linux-kernel@codethink.co.uk, netdev@vger.kernel.org, nobuhiro.iwamatsu.yj@renesas.com, magnus.damm@opensource.se, cm-hiep@jinso.co.jp To: Yoshihiro Shimoda Return-path: Received: from kirsty.vergenet.net ([202.4.237.240]:57411 "EHLO kirsty.vergenet.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751102AbaFDB07 (ORCPT ); Tue, 3 Jun 2014 21:26:59 -0400 Content-Disposition: inline In-Reply-To: <538E685A.1000505@renesas.com> Sender: netdev-owner@vger.kernel.org List-ID: On Wed, Jun 04, 2014 at 09:29:14AM +0900, Yoshihiro Shimoda wrote: > Hi Ben, > > (2014/06/03 20:21), Ben Dooks wrote: > > The current behaviour of the sh_eth driver is not to use the RNC bit > > for the receive ring. This means that every packet recieved is not only > > generating an IRQ but it also stops the receive ring DMA as well until > > the driver re-enables it after unloading the packet. > > > > This means that a number of the following errors are generated due to > > the receive packet FIFO overflowing due to nowhere to put packets: > > > > net eth0: Receive FIFO Overflow > > > > Since feedback from Yoshihiro Shimoda shows that every supported LSI > > for this driver should have the bit enabled it seems the best way is > > to remove the RMCR default value from the per-system data and just > > write it when initialising the RMCR value. This is discussed in > > the message (http://www.spinics.net/lists/netdev/msg284912.html). > > > > I have tested the RMCR_RNC configuration with NFS root filesystem and > > the driver has not failed yet. There are further test reports from > > Sergei Shtylov and others for both the R8A7790 and R8A7791. > > > > There is also feedback fron Cao Minh Hiep[1] which reports the > > same issue in (http://comments.gmane.org/gmane.linux.network/316285) > > showing this fixes issues with losing UDP datagrams under iperf. > > > > Tested-by: Sergei Shtylyov > > Signed-off-by: Ben Dooks > > Thank you very much for the patch. > > Acked-by: Yoshihiro Shimoda If this patch is fine by Shimoda-san then its fine be me too. Acked-by: Simon Horman