From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= <mans@mansr.com>
Subject: Re: [PATCH v3 2/4] net: nb8800: Simplify nb8800_pause_config()
Date: Wed, 15 Nov 2017 15:36:22 +0000
Message-ID: <yw1xmv3nzh8p.fsf@mansr.com>
References: <230165aa-eaf1-6e2b-7ff3-45b3ee4ffc62@sigmadesigns.com>
        <dd0c2014-8ef9-749c-16d3-6a56f4161658@sigmadesigns.com>
        <yw1x1sl12fx8.fsf@mansr.com>
        <569542b1-8e56-d7da-f7a0-affd89bfed62@sigmadesigns.com>
        <yw1xk1yt0zbp.fsf@mansr.com>
        <6f534b2b-f69a-bda5-dc5b-0281bf0df129@sigmadesigns.com>
        <20171115141707.GB2130@lunn.ch>
        <01be0b9e-3d6c-bd1e-6b92-e2274ffeea5a@sigmadesigns.com>
        <20171115150331.GA29642@lunn.ch>
        <e3dfc32f-7052-603d-659a-0a7d9d7453b0@sigmadesigns.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8BIT
Cc: Andrew Lunn <andrew@lunn.ch>,
        Florian Fainelli <f.fainelli@gmail.com>,
        Mason <slash.tmp@free.fr>, netdev <netdev@vger.kernel.org>,
        Thibaud Cornic <thibaud_cornic@sigmadesigns.com>,
        David Miller <davem@davemloft.net>,
        "Linux ARM" <linux-arm-kernel@lists.infradead.org>
To: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Return-path: <netdev-owner@vger.kernel.org>
Received: from unicorn.mansr.com ([81.2.72.234]:60808 "EHLO unicorn.mansr.com"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S932313AbdKOPgY (ORCPT <rfc822;netdev@vger.kernel.org>);
        Wed, 15 Nov 2017 10:36:24 -0500
In-Reply-To: <e3dfc32f-7052-603d-659a-0a7d9d7453b0@sigmadesigns.com> (Marc
        Gonzalez's message of "Wed, 15 Nov 2017 16:19:56 +0100")
Sender: netdev-owner@vger.kernel.org
List-ID: <netdev.vger.kernel.org>

Marc Gonzalez <marc_gonzalez@sigmadesigns.com> writes:

> On 15/11/2017 16:03, Andrew Lunn wrote:
>
>> On Wed, Nov 15, 2017 at 03:33:47PM +0100, Marc Gonzalez wrote:
>> 
>>> On 15/11/2017 15:17, Andrew Lunn wrote:
>>>
>>> In our local branch, I have completely disabled flow control support,
>>> so I don't have to worry about this problem.
>> 
>> That is an interesting statement. You now know there is an issue here,
>> your solution is to fix your private branch and leave mainline as is.
>
> All my patches are NACKed, what would you have me do?
>
> Moreover, mainline still has the nb8800_dma_stop() work-around,
> which Mans has never seen hang.

Here's the thing, if that trick doesn't work, then the dma queue filling
up from real traffic will also hang the controller, which is a much
bigger problem.  Your test today suggests that this might be the case.

-- 
Måns Rullgård