From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Date: Fri, 28 Mar 2014 19:38:32 +0000 Subject: Re: [RFC] sh_eth: use RNC mode for R8A7790 Message-Id: <5335DDC7.8040400@cogentembedded.com> List-Id: References: <1396025185-7911-1-git-send-email-ben.dooks@codethink.co.uk> In-Reply-To: <1396025185-7911-1-git-send-email-ben.dooks@codethink.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ben Dooks , netdev@vger.kernel.org Cc: linux-sh@vger.kernel.org, magnus.damm@opensource.se, nobuhiro.iwamatsu.yj@renesas.com 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