Re: A weird problem of Realtek r8168 after resume from S3

[Chris Chiu]

On Fri, Dec 14, 2018 at 3:37 PM Heiner Kallweit <hkallweit1@xxxxxxxxx> wrote:
>
> On 14.12.2018 04:33, Chris Chiu wrote:
> > On Thu, Dec 13, 2018 at 10:20 AM Chris Chiu <chiu@xxxxxxxxxxxx> wrote:
> >>
> >> Hi,
> >>     We got an acer laptop which has a problem with ethernet networking after
> >> resuming from S3. The ethernet is popular realtek r8168. The lspci shows as
> >> follows.
> >> 02:00.1 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd.
> >> RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 12)
> >>
> Helpful would be a "dmesg | grep r8169", especially chip name + XID.
>
[   22.362774] r8169 0000:02:00.1 (unnamed net_device)
(uninitialized): mac_version = 0x2b
[   22.365580] libphy: r8169: probed
[   22.365958] r8169 0000:02:00.1 eth0: RTL8411, 00:e0:b8:1f:cb:83,
XID 5c800800, IRQ 38
[   22.365961] r8169 0000:02:00.1 eth0: jumbo features [frames: 9200
bytes, tx checksumming: ko]

> >>     The problem is the ethernet is not accessible after resume. Pinging via
> >> ethernet always shows the response `Destination Host Unreachable`. However,
> >> the interesting part is, when I run tcpdump to monitor the problematic ethernet
> >> interface, the networking is back to alive. But it's dead again after
> >> I stop tcpdump.
> >> One more thing, if I ping the problematic machine from others, it achieves the
> >> same effect as above tcpdump. Maybe it's about the register setting for RX path?
> >>
> You could compare the register dumps (ethtool -d) before and after S3 sleep
> to find out whether there's a difference.
>

Actually, I just found I lead the wrong direction. The S3 suspend does
help to reproduce,
but it's not necessary. All I need to do is ping around 5 mins and the
network connection
fails.  And I also find one thing interesting, disabling the  MSI-X
interrupt like commit
[d49c88d7677ba737e9d2759a87db0402d5ab2607] can fix this problem.
Although I don't
understand the root cause. Anything I can do to help?

> >>     I tried the latest 4.20 rc version but the problem still there. I
> >> also tried some
> >> hw_reset or init thing in the resume path but no effect. Any
> >> suggestion for this?
> >> Thanks
> >>
> Did previous kernel versions work? If it's a regression, a bisect would be
> appreciated, because with the chip versions I've got I can't reproduce the issue.
>
> >> Chris
> >
> > Gentle ping. Any additional information required?
> >
> > Chris
> >
> Heiner