netdev - Re: RTL8402 stops working after hibernate/resume

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Message-ID: <aa997635-a5b5-75e3-8a30-a77acb2adf35@gmail.com>
Date:   Fri, 25 Sep 2020 11:44:09 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Petr Tesarik <ptesarik@...e.cz>
Cc:     Realtek linux nic maintainers <nic_swsd@...ltek.com>,
        netdev@...r.kernel.org
Subject: Re: RTL8402 stops working after hibernate/resume

On 25.09.2020 10:54, Petr Tesarik wrote:
> On Fri, 25 Sep 2020 09:30:37 +0200
> Petr Tesarik <ptesarik@...e.cz> wrote:
> 
>> On Thu, 24 Sep 2020 22:12:24 +0200
>> Heiner Kallweit <hkallweit1@...il.com> wrote:
>>
>>> On 24.09.2020 21:14, Petr Tesarik wrote:  
>>>> On Wed, 23 Sep 2020 11:57:41 +0200
>>>> Heiner Kallweit <hkallweit1@...il.com> wrote:
>>>>   
>>>>> On 03.09.2020 10:41, Petr Tesarik wrote:  
>>>>>> Hi Heiner,
>>>>>>
>>>>>> this issue was on the back-burner for some time, but I've got some
>>>>>> interesting news now.
>>>>>>
>>>>>> On Sat, 18 Jul 2020 14:07:50 +0200
>>>>>> Heiner Kallweit <hkallweit1@...il.com> wrote:
>>>>>>     
>>>>>>> [...]
>>>>>>> Maybe the following gives us an idea:
>>>>>>> Please do "ethtool -d <if>" after boot and after resume from suspend,
>>>>>>> and check for differences.    
>>>>>>
>>>>>> The register dump did not reveal anything of interest - the only
>>>>>> differences were in the physical addresses after a device reopen.
>>>>>>
>>>>>> However, knowing that reloading the driver can fix the issue, I copied
>>>>>> the initialization sequence from init_one() to rtl8169_resume() and
>>>>>> gave it a try. That works!
>>>>>>
>>>>>> Then I started removing the initialization calls one by one. This
>>>>>> exercise left me with a call to rtl_init_rxcfg(), which simply sets the
>>>>>> RxConfig register. In other words, these is the difference between
>>>>>> 5.8.4 and my working version:
>>>>>>
>>>>>> --- linux-orig/drivers/net/ethernet/realtek/r8169_main.c	2020-09-02 22:43:09.361951750 +0200
>>>>>> +++ linux/drivers/net/ethernet/realtek/r8169_main.c	2020-09-03 10:36:23.915803703 +0200
>>>>>> @@ -4925,6 +4925,9 @@
>>>>>>  
>>>>>>  	clk_prepare_enable(tp->clk);
>>>>>>  
>>>>>> +	if (tp->mac_version == RTL_GIGA_MAC_VER_37)
>>>>>> +		RTL_W32(tp, RxConfig, RX128_INT_EN | RX_DMA_BURST);
>>>>>> +
>>>>>>  	if (netif_running(tp->dev))
>>>>>>  		__rtl8169_resume(tp);
>>>>>>  
>>>>>> This is quite surprising, at least when the device is managed by
>>>>>> NetworkManager, because then it is closed on wakeup, and the open
>>>>>> method should call rtl_init_rxcfg() anyway. So, it might be a timing
>>>>>> issue, or incorrect order of register writes.
>>>>>>     
>>>>> Thanks for the analysis. If you manually bring down and up the
>>>>> interface, do you see the same issue?  
>>>>
>>>> I'm not quite sure what you mean, but if the interface is configured
>>>> (and NetworkManager is stopped), I can do 'ip link set eth0 down' and
>>>> then 'ip link set eth0 up', and the interface is fully functional.
>>>>   
>>>>> What is the value of RxConfig when entering the resume function?  
>>>>
>>>> I added a dev_info() to rtl8169_resume(). First with NetworkManager
>>>> active (i.e. interface down on suspend):
>>>>
>>>> [  525.956675] r8169 0000:03:00.2: RxConfig after resume: 0x0002400f
>>>>
>>>> Then I re-tried with NetworkManager stopped (i.e. interface up on
>>>> suspend). Same result:
>>>>
>>>> [  785.413887] r8169 0000:03:00.2: RxConfig after resume: 0x0002400f
>>>>
>>>> I hope that's what you were asking for...
>>>>
>>>> Petr T
>>>>   
>>>
>>> rtl8169_resume() has been changed in 5.9, therefore the patch doesn't
>>> apply cleanly on older kernel versions. Can you test the following
>>> on a 5.9-rc version or linux-next?  
>>
>> I tried installing 5.9-rc6, but it freezes hard at boot, last message is:
>>
>> [   14.916259] libphy: r8169: probed
>>

This doesn't necessarily mean that the r8169 driver crashes the system.
Other things could run in parallel. It freezes w/o any message?

>> At this point, I suspect you're right that the BIOS is seriously buggy.
>> Let me check if ASUSTek has released any update for this model.
> 
> Hm, it took me about an hour wondering why I cannot flash the 314 update, but then I finally noticed that this was for X543, while mine is an X453... *sigh*
> 
> So, I'm at BIOS version 214, released in 2015, and that's the latest version. There are some older versions available, but the BIOS Flash utility won't let me downgrade.
> 
> Does it make sense to bisect the change that broke the driver for me, or should I rather dispose of this waste^Wlaptop in an environmentally friendly manner? I mean, would you eventually accept a workaround for a few machines with a broken BIOS?
> 
If the workaround is small and there's little chance to break other stuff: then usually yes.
If you can spend the effort to bisect the issue, this would be appreciated.


> Petr T
> 
Heiner