From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ben Dooks Subject: Re: [RFC] sh_eth: use RNC mode for R8A7790 Date: Mon, 14 Apr 2014 13:47:53 +0100 Message-ID: <534BD8F9.5080105@codethink.co.uk> References: <1396025185-7911-1-git-send-email-ben.dooks@codethink.co.uk> <5335DDC7.8040400@cogentembedded.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-sh@vger.kernel.org, magnus.damm@opensource.se, nobuhiro.iwamatsu.yj@renesas.com To: Sergei Shtylyov , netdev@vger.kernel.org Return-path: In-Reply-To: <5335DDC7.8040400@cogentembedded.com> Sender: linux-sh-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 28/03/14 20:38, Sergei Shtylyov wrote: > Hello. > > On 03/28/2014 07:46 PM, 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 > >> Setting the RMCR_RNC configuration has so far been tested with an NFS >> root filesystem and the driver has not failed yet. It is not yet known >> why this is not set for R8A779x operation > > The reason is simple: it's not set on almost all 100 Mbs devices > except SH7757 (and most recently added R7S72100), so this was a matter > of copy-paste. I've had setting this bit on at least R-Car devices on my > aganda for some time but couldn't get to it yet. > >> (Feedback on this issue or other testing is welcome) > > OK, I'll try it with netperf UDP test known to generate handful of > the aforementioned errors, when I have time. > > WBR, Sergei Has anyone had time to look at this? -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius