netdev - Re: [RFC] sh_eth: use RNC mode for R8A7790

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <535AF5A0.6010206@cogentembedded.com>
Date:	Sat, 26 Apr 2014 03:54:08 +0400
From:	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>
To:	Geert Uytterhoeven <geert@...ux-m68k.org>,
	Ben Dooks <ben.dooks@...ethink.co.uk>
CC:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Linux-sh list <linux-sh@...r.kernel.org>,
	magnus.damm@...nsource.se,
	Nobuhiro Iwamatsu <nobuhiro.iwamatsu.yj@...esas.com>
Subject: Re: [RFC] sh_eth: use RNC mode for R8A7790

Hello.

On 04/14/2014 08:48 PM, Geert Uytterhoeven 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.

>>> Has anyone had time to look at this?

>> I gave it a try on Koelsch (it does apply to r8a7791, too, right?), and didn't
>> see any good or ill effects. Just using NFS root and generating some I/O,
>> so nothing fancy.

> FWIW, I still have "renesas,no-ether-link" in the ethernet node in DT.

    You shouldn't need it anymore if you're using recent devel branch of the 
renesas.git repo: it already has the necessary PHY driver and device tree 
changes to avoid the issue which specifying that prop fixed.

> Gr{oetje,eeting}s,

WBR, Sergei

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html