From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Date: Fri, 25 Apr 2014 23:55:33 +0000 Subject: Re: [RFC] sh_eth: use RNC mode for R8A7790 Message-Id: <535AF5F5.1000703@cogentembedded.com> List-Id: References: <1396025185-7911-1-git-send-email-ben.dooks@codethink.co.uk> <5335DDC7.8040400@cogentembedded.com> <534BD8F9.5080105@codethink.co.uk> In-Reply-To: <534BD8F9.5080105@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 04/14/2014 04:47 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? OK, I've finally tried netperf and couldn't get it to reproduce these errors on any R-Car gen2 board. I was only able to reproduce this error on a new R8A7791 board during NFS boot, and applying the patch seems to have helped. So you can add my: Tested-by: Sergei Shtylyov WBR, Sergei