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Subject: Re: [PATCH] r8169: don't use MSI-X on RTL8106e
To:     David Miller <davem@davemloft.net>
Cc:     jian-hong@endlessm.com, nic_swsd@realtek.com,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux@endlessm.com
References: <20180815062110.16155-1-jian-hong@endlessm.com>
 <20180816.122131.604270853620318143.davem@davemloft.net>
 <458efbf9-5971-653a-e7cd-8c56ba055648@gmail.com>
 <20180816.123958.750435252621963789.davem@davemloft.net>
From:   Heiner Kallweit <hkallweit1@gmail.com>
Message-ID: <ac30d4e6-6411-09e6-1205-96e3e8e29f6f@gmail.com>
Date:   Thu, 16 Aug 2018 21:50:48 +0200
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On 16.08.2018 21:39, David Miller wrote:
> From: Heiner Kallweit <hkallweit1@gmail.com>
> Date: Thu, 16 Aug 2018 21:37:31 +0200
> 
>> On 16.08.2018 21:21, David Miller wrote:
>>> From: <jian-hong@endlessm.com>
>>> Date: Wed, 15 Aug 2018 14:21:10 +0800
>>>
>>>> Found the ethernet network on ASUS X441UAR doesn't come back on resume
>>>> from suspend when using MSI-X.  The chip is RTL8106e - version 39.
>>>
>>> Heiner, please take a look at this.
>>>
>>> You recently disabled MSI-X on RTL8168g for similar reasons.
>>>
>>> Now that we've seen two chips like this, maybe there is some other
>>> problem afoot.
>>>
>> Thanks for the hint. I saw it already and just contacted Realtek
>> whether they are aware of any MSI-X issues with particular chip
>> versions. With the chip versions I have access to MSI-X works fine.
>>
>> There's also the theoretical option that the issues are caused by
>> broken BIOS's. But so far only chip versions have been reported
>> which are very similar, at least with regard to version number
>> (2x VER_40, 1x VER_39). So they may share some buggy component.
>>
>> Let's see whether Realtek can provide some hint.
>> If more chip versions are reported having problems with MSI-X,
>> then we could switch to a whitelist or disable MSI-X in general.
> 
> It could be that we need to reprogram some register(s) on resume,
> which normally might not be needed, and that is what is causing the
> problem with some chips.
> 
Indeed. That's what I'm checking with Realtek.
In the register list in the r8169 driver there's one entry which
seems to indicate that there are MSI-X specific settings.
However this register isn't used, and the r8168 vendor driver
uses only MSI. And there are no public datasheets.