netdev - Re: [Patch net-next v2 4/4] net: fec: Workaround for imx6sx enet tx hang when enable three queues

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] [day] [month] [year] [list]

Date:	Tue, 16 Sep 2014 16:24:20 -0500
From:	Zhi Li <lznuaa@...il.com>
To:	Fabio Estevam <festevam@...il.com>
Cc:	Frank Li <Frank.Li@...escale.com>,
	Duan Fugang-B38611 <b38611@...escale.com>,
	"David S. Miller" <davem@...emloft.net>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	Shawn Guo <shawn.guo@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [Patch net-next v2 4/4] net: fec: Workaround for imx6sx enet tx
 hang when enable three queues

On Tue, Sep 16, 2014 at 3:52 PM, Fabio Estevam <festevam@...il.com> wrote:
> On Tue, Sep 16, 2014 at 2:58 PM,  <Frank.Li@...escale.com> wrote:
>> From: Fugang Duan <B38611@...escale.com>
>>
>> When enable three queues on imx6sx enet, and then do tx performance
>> test with iperf tool, after some time running, tx hang.
>>
>> Found that:
>>         If uDMA is running, software set TDAR may cause tx hang.
>>         If uDMA is in idle, software set TDAR don't cause tx hang.
>>
>> There is a TDAR race condition for mutliQ when the software sets TDAR
>> and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles).
>> This will cause the udma_tx and udma_tx_arbiter state machines to hang.
>> The issue exist at i.MX6SX enet IP.
>>
>> So, the Workaround is checking TDAR status four time, if TDAR cleared by
>> hardware and then write TDAR, otherwise don't set TDAR.
>>
>> The patch is only one Workaround for the issue TKT210582.
>
> As Shawn pointed out, it is better to use the ERR007885 instead of an
> internal bug numbering.

Sorry, I forget change commit message.

best regards
Frank Li
--
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