Hate that Updates then no connection

[Qqmike]

Thanks for your reply. I don't think I should monkey with this any further! Sure don't want to get into 'updating initramfs files'! (brings back memories of GRUB Legacy, doing stuff like that ...)
Let's see what happens with the next kernel update.
Thanks, again.

[Schwarzer Kater]

[…] Sure don't want to get into 'updating initramfs files'! […]

This is what is done at least with every kernel update anyway… So to do this would be nothing out of the ordinary. See e.g. man update-initramfs for some more info.
The question for me that still remains is if you would have to blacklist the r8169 before or take any other measures…

Out of curiosity I would appreciate it if you could write again after the next kernel update (even if you have not done anything else until then).

Another information that you did not give us yet is if your modem (or any other device in your network that you might connect your computer to) is capable of a 2.5 Gbps connection at all… This information could be useful for testing purposes down the road.

[Qqmike]

OK, got it! Thanks, will do. Edit: see next post ...

[Qqmike]

The modem is a router-modem combo. It is old! Provided by my DSL provider (centuryLink.net):

ZyXel router-modem
Features of the Zyxel C1000Z
WiFi supported: 2.4 GHz 802.11 b/g/n
IP compatibility: IPv4, IPv6

I have a technical data sheet on it -- it is on the Internet, https://www.centurylink.com/content/...-datasheet.pdf,
but I don't really understand this stuff.

I am certain that this modem is out of date, it needs a firmware update or replacement. BUT ... it is serving very well, no serious hiccups or problems with WiFi.

I did find this, too:

Works with these CenturyLink internet services:
ADSL – up to 7 Mbps
ADSL2 – up to 20 Mbps
VDSL – up to 40 Mbps
Note: Listed speeds reflect the maximum download speed the technology can deliver on CenturyLink services. In-home speeds may differ based on router setup, devices and other factors.

It is on my to-do list to buy another newer modem from them ... ... just can't get around to it ...

[Schwarzer Kater]

This modem is about 10 years old - it certainly does not support 2.5 Gbps Ethernet but either 100 Mbps or 1 Gbps at most.
I could not quickly find exact technical specifications of its 4 Ethernet ports anywhere in their documentation or on their website.

So the main focus would be to prevent you from having to reset your network connection after kernel updates, because as long as this modem remains the central device of your Ethernet network the internal network speed can only get as fast as the modem's Ethernet connections are capabale of (presumably 100 Mbps or 1 Gbps).
And therefore it does not matter if the Ethernet port of your computer uses a speed of 2.5 or 1 Gbps… Only if the right kernel driver/module will/can prevent you from having to reset your network connection after (kernel) updates (and for that to happen your computer had to actually use the right driver/module for Realtek RTL8125 IMHO).

[Qqmike]

So, it is r8125; but why then, or how then, did r8169 enter the picture?
Btw, thanks for spending your time looking into this.
I will try to call the provider soon to assess either a firmware update or a new modem.

[Schwarzer Kater]

r8169 is probably included by default to cover a wide range of Realtek chipsets and is used as a fallback in your case (your port is backward compatible to at least 1 Gbps and 100 Mbps).

No need to change your modem if it works fine, though.
Your (private) internet connection will not become any faster if you connect the computer to the modem with 2.5 Gbps (the download speed of your internet connection is probably somewhere between 50 and 250 Mbps - ask yout internet provider or use something like https://www.breitbandmessung.de/test to find out - sorry German site)…

[Qqmike]

But WiFi might work better with a newer modem, or at least updated firmware, I think.

[Schwarzer Kater]

It might, this depends on your WiFi - but as a rule of thumb one should always prefer a cable (fiber-optic, copper, …) to a wireless connection when designing a network, if possible.

[Qqmike]

I just had a PC freeze-up -- I couldn't even move the mouse pointer. Had to do a hard shutdown of the PC, then it booted back up OK.

But I did get this (which occurred as the PC was booting back up AFTER the freeze-up):

journalctl -b -a
​Jul 30 09:45:31 mike-System-Product-Name kernel: idma64 idma64.0: Found Intel integrated DMA 64-bit
Jul 30 09:45:31 mike-System-Product-Name kernel: r8169 0000:03:00.0 eth0: RTL8125B, 04:42:1a:0c:7d:bd, XID 64>
Jul 30 09:45:31 mike-System-Product-Name kernel: r8169 0000:03:00.0 eth0: jumbo features [frames: 9194 bytes,>
Jul 30 09:45:31 mike-System-Product-Name kernel: r8125: loading out-of-tree module taints kernel.
Jul 30 09:45:31 mike-System-Product-Name kernel: r8125: module verification failed: signature and/or required>
Jul 30 09:45:31 mike-System-Product-Name kernel: asus_wmi: ASUS WMI generic driver loaded
Jul 30 09:45:31 mike-System-Product-Name kernel: r8169 0000:03:00.0 enp3s0: renamed from eth0

[Schwarzer Kater]

Every (unsigned) "third party" module "taints" the kernel. If you use "secure boot" you will have to verify/sign additional modules for that purpose.
So

Jul 30 09:45:31 mike-System-Product-Name kernel: r8125: loading out-of-tree module taints kernel.
Jul 30 09:45:31 mike-System-Product-Name kernel: r8125: module verification failed: signature and/or required key missing - tainting kernel>​

is nothing out of the ordinary.
You will see similar lines in every log file of an *Ubuntu installation that uses e.g. the proprietary Nvidia driver (if the driver has not been explicitly and manually signed for "secure boot" by the user).

If you suspect the r8125 module to be responsible for your crash, just sudo apt purge r8125-dkms …
But according to this journalctl output alone that you posted, I can see no reason for this suspicion (it is not used anyway at the moment…).

[Qqmike]

No, I am not suspicious of the r8125. I was having freezes (as you may recall from another thread I posted on it, we suspected maybe KWin), but this time I couldn't do anything with the PC. Couldn't even do a hard re-start (by pressing the restart button on the PC case) -- had to do a hard shutdown (pressing and holding the power button on the PC case). Strange. I used that journalctl command, but I couldn't get it to go back in history, say back to when the actual freeze occurred 5 minutes earlier.

[Schwarzer Kater]

Yes, I remember…
sudo journalctl -b -1 -a would be the one before the current boot.

PS: Fortunately I have not had these "hard freezes" for years - only recently again with the 6.3.x kernels (in Fedora, openSUSE TW and Arch)… 6.4.x kernels work without any problems so far - must have been sth. specific about my hardware in combination with these 6.3.x kernels.

[Qqmike]

Thanks, again. 👍