Lenovo RTL8153-04 jumbo frames on ARM

[Lionel Élie Mamane]

Hi,

After much head-scratching of why I could not SSH-connect to the
computer in my basement (the SSH connection process would start but
then stall), while everything seemed normal on the physical console, I
understood that the USB-C Ethernet NIC that came with my Lenovo X13s
seems not to work with jumbo frames.

I dusted off my old am64 laptop, connected the same USB-C Ethernet NIC
and there with kernel 5.10.0-21-amd64, it works with 9000 bytes Jumbo
Frames via a USB-C to USB-A adapter, no trouble. Same when connected
to a ppc64le machine running 6.10.11+bpo-powerpc64le-64k over the same
USB-C to USB-A adapter.

So it seem to be aarch64-specific :-/ Anybody knows whether this a
general problem for this chipset and/or ethernet in general on
aarch64? Is it worth picking up another USB-C NIC and trying?

Since Debian kernels don't work on the ThinkPad X13s yet, I run a
6.6.12 kernel compiled from https://github.com/steev/linux.git branch
lenovo-x13s-linux-6.6.y as of 2024-01-19 (date of last commit). Just
haven't upgraded since. Could be an error I made in the kernel's
config, but I cannot imagine what? On the aarch64 laptop, "ip link
show" lists an MTU of 9000, so the kernel thinks it set it correctly.

Theoretically it could also be USB-C specific, but that seems rather
unlikely?

Thanks in advance for any idea or hint,

[Emanuele Rocca]

Hi Lionel,

Post by Lionel Élie Mamane
Since Debian kernels don't work on the ThinkPad X13s yet, I run a
6.6.12 kernel compiled from https://github.com/steev/linux.git branch
lenovo-x13s-linux-6.6.y as of 2024-01-19 (date of last commit).

All X13s users I know run Trixie (testing) instead of Bookworm. The main
reason for this is that indeed as you said Bookworm kernels (6.1.x)
don't have X13s support.

However, if you want to run Bookworm I would suggest trying the kernels
from backports (6.10.x):
https://backports.debian.org/Instructions/

If you do give it a shot, please let us know whether that fixes the
problem you've seen with jumbo frames.

More general information about Debian on the X13s here:
https://wiki.debian.org/InstallingDebianOn/Thinkpad/X13s

[Lionel Élie Mamane]

Post by Emanuele Rocca

Post by Lionel Élie Mamane
Since Debian kernels don't work on the ThinkPad X13s yet, I run a
6.6.12 kernel compiled from https://github.com/steev/linux.git
branch lenovo-x13s-linux-6.6.y as of 2024-01-19 (date of last
commit).

All X13s users I know run Trixie (testing) instead of Bookworm. The
main reason for this is that indeed as you said Bookworm kernels
(6.1.x) don't have X13s support.
https://wiki.debian.org/InstallingDebianOn/Thinkpad/X13s

I wasn't aware pristine Debian trixie/sid kernels had x13s support
now. I never got them to boot; I tried the latest sid one every few
months, but I never had any luck.

I reviewed the current version of the wiki page; I did the things that
looked relevant:

* hardcoding the module list in /etc/initramfs-tools/modules

* adding "arm64.nopauth" to the linux parameters; I also removed
"clk_ignore_unused" which my self-compiled 6.6.12 required, but
apparently Debian 6.11.7-1 does not.

Booting into Linux kernel 6.11.7-1 fixed the jumbo frame issue. Thanks
very much!!!

I used to install the dtb files as
/boot/efi/dtb/f249803d-0d95-54f3-a28f-f2614a03f3b.dtb
the wiki page says to install them as
/boot/efi/sc8280xp-lenovo-thinkpad-x13s.dtb

I have two EFI boot entries; one is called "debian" and probably was
created automatically by something? It boots into
HD(1,GPT,${LONG UUID},0x800,0x100000)/File(\EFI\debian\grubaa64.efi)
the other is clearly created manually by me (must be following the
instructions on [1]) and boots into
VenHw(${ANOTHER LONG UUID})/PcieRoot(0x2)/Pci(0x0,0x0)/NVMe(0x1,00-25-38-EC-21-B9-CC-B1)/HD(1,GPT,${LONG UUID},0x800,0x100000)/File(\EFI\debian\DtbLoaeder.efi)

I guess that these two different boot loaders methods are what makes
the difference as to where the .dtb file is loaded from?

[1] https://docs.google.com/document/d/1WuxE-42ZeOkKAft5FuUk6C2fonkQ8sqNZ56ZmZ49hGI
Linaro -- Instructions for flashing and installing the Debian installer

--
Lionel