netdev - Re: network problems with r8169

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Message-ID: <9cab7996-d801-0ae5-9e82-6d24eeb8d7c7@gmail.com>
Date:   Sat, 20 Jul 2019 11:11:16 +0200
From:   Heiner Kallweit <hkallweit1@...il.com>
To:     Thomas Voegtle <tv@...96.de>
Cc:     linux-kernel@...r.kernel.org,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: Re: network problems with r8169

On 19.07.2019 23:12, Thomas Voegtle wrote:
> On Fri, 19 Jul 2019, Heiner Kallweit wrote:
> 
>> On 18.07.2019 20:50, Thomas Voegtle wrote:
>>>
>>> Hello,
>>>
>>> I'm having network problems with the commits on r8169 since v5.2. There are ping packet loss, sometimes 100%, sometimes 50%. In the end network is unusable.
>>>
>>> v5.2 is fine, I bisected it down to:
>>>
>>> a2928d28643e3c064ff41397281d20c445525032 is the first bad commit
>>> commit a2928d28643e3c064ff41397281d20c445525032
>>> Author: Heiner Kallweit <hkallweit1@...il.com>
>>> Date:   Sun Jun 2 10:53:49 2019 +0200
>>>
>>>     r8169: use paged versions of phylib MDIO access functions
>>>
>>>     Use paged versions of phylib MDIO access functions to simplify
>>>     the code.
>>>
>>>     Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
>>>     Signed-off-by: David S. Miller <davem@...emloft.net>
>>>
>>>
>>> Reverting that commit on top of v5.2-11564-g22051d9c4a57 fixes the problem
>>> for me (had to adjust the renaming to r8169_main.c).
>>>
>>> I have a:
>>> 04:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd.
>>> RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev
>>> 0c)
>>>         Subsystem: Biostar Microtech Int'l Corp Device [1565:2400]
>>>         Kernel driver in use: r8169
>>>
>>> on a BIOSTAR H81MG motherboard.
>>>
>> Interesting. I have the same chip version (RTL8168g) and can't reproduce
>> the issue. Can you provide a full dmesg output and test the patch below
>> on top of linux-next? I'd be interested in the WARN_ON stack traces
>> (if any) and would like to know whether the experimental change to
>> __phy_modify_changed helps.
>>
>>>
>>> greetings,
>>>
>>>   Thomas
>>>
>>>
>> Heiner
>>
>>
>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c b/drivers/net/ethernet/realtek/r8169_main.c
>> index 8d7dd4c5f..26be73000 100644
>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>> @@ -1934,6 +1934,8 @@ static int rtl_get_eee_supp(struct rtl8169_private *tp)
>>     struct phy_device *phydev = tp->phydev;
>>     int ret;
>>
>> +    WARN_ON(phy_read(phydev, 0x1f));
>> +
>>     switch (tp->mac_version) {
>>     case RTL_GIGA_MAC_VER_34:
>>     case RTL_GIGA_MAC_VER_35:
>> @@ -1957,6 +1959,8 @@ static int rtl_get_eee_lpadv(struct rtl8169_private *tp)
>>     struct phy_device *phydev = tp->phydev;
>>     int ret;
>>
>> +    WARN_ON(phy_read(phydev, 0x1f));
>> +
>>     switch (tp->mac_version) {
>>     case RTL_GIGA_MAC_VER_34:
>>     case RTL_GIGA_MAC_VER_35:
>> @@ -1980,6 +1984,8 @@ static int rtl_get_eee_adv(struct rtl8169_private *tp)
>>     struct phy_device *phydev = tp->phydev;
>>     int ret;
>>
>> +    WARN_ON(phy_read(phydev, 0x1f));
>> +
>>     switch (tp->mac_version) {
>>     case RTL_GIGA_MAC_VER_34:
>>     case RTL_GIGA_MAC_VER_35:
>> @@ -2003,6 +2009,8 @@ static int rtl_set_eee_adv(struct rtl8169_private *tp, int val)
>>     struct phy_device *phydev = tp->phydev;
>>     int ret = 0;
>>
>> +    WARN_ON(phy_read(phydev, 0x1f));
>> +
>>     switch (tp->mac_version) {
>>     case RTL_GIGA_MAC_VER_34:
>>     case RTL_GIGA_MAC_VER_35:
>> diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
>> index 16667fbac..1aa1142b8 100644
>> --- a/drivers/net/phy/phy-core.c
>> +++ b/drivers/net/phy/phy-core.c
>> @@ -463,12 +463,10 @@ int __phy_modify_changed(struct phy_device *phydev, u32 regnum, u16 mask,
>>         return ret;
>>
>>     new = (ret & ~mask) | set;
>> -    if (new == ret)
>> -        return 0;
>>
>> -    ret = __phy_write(phydev, regnum, new);
>> +    __phy_write(phydev, regnum, new);
>>
>> -    return ret < 0 ? ret : 1;
>> +    return new != ret;
>> }
>> EXPORT_SYMBOL_GPL(__phy_modify_changed);
>>
>>
> 
> Took your patch on top of next-20190719.
> See attached dmesg.
> It didn't work. Same thing, lots of ping drops, no usable network.
> 
> like that:
> 44 packets transmitted, 2 received, 95% packet loss, time 44005ms
> 
> 
> Maybe important:
> I build a kernel with no modules.
> 
> I have to power off when I booted a kernel which doesn't work, a (soft) reboot into a older kernel (e.g. 4.9.y)  doesn't
> fix the problem. Powering off and on does.
> 

Then, what you could do is reversing the hunks of the patch step by step.
Or make them separate patches and bisect.
Relevant are the hunks from point 1 and 2.

1. first 5 hunks (I don't think you have to reverse them individually)
   EEE-related

2. rtl8168g_disable_aldps, rtl8168g_phy_adjust_10m_aldps, rtl8168g_1_hw_phy_config
   all of these hunks are in the path for RTL8168g

3. rtl8168h_1_hw_phy_config, rtl8168h_2_hw_phy_config, rtl8168ep_1_hw_phy_config,
   rtl8168ep_2_hw_phy_config
   not in the path for RTL8168g

> 
> greetings,
> 
>       Thomas
Heiner