User reports indicate that at least some other AR81xx parts have the same problem

@ivy Any details which parts have the same problem ?

In D50558#1154277, @zlei wrote:

@ivy Any details which parts have the same problem ?

it was reported on AR8171:

alc0@pci0:3:0:0: class=0x020000 rev=0x10 hdr=0x00 vendor=0x1969 device=0x10a1 subvendor=0x1849 subdevice=0x10a1
vendor = 'Qualcomm Atheros'
device = 'QCA8171 Gigabit Ethernet'
class = network
subclass = ethernet

i am not 100% convinced this is a hardware problem since Linux appears to enable MSI-X by default, but either way it doesn't work. (i spent a long time looking at this originally and could not work out what Linux was doing differently, and hardware documentation seems to be unavailable.)

In D50558#1154278, @ivy wrote:

In D50558#1154277, @zlei wrote:

@ivy Any details which parts have the same problem ?

it was reported on AR8171:

alc0@pci0:3:0:0: class=0x020000 rev=0x10 hdr=0x00 vendor=0x1969 device=0x10a1 subvendor=0x1849 subdevice=0x10a1
vendor = 'Qualcomm Atheros'
device = 'QCA8171 Gigabit Ethernet'
class = network
subclass = ethernet

i am not 100% convinced this is a hardware problem since Linux appears to enable MSI-X by default, but either way it doesn't work. (i spent a long time looking at this originally and could not work out what Linux was doing differently, and hardware documentation seems to be unavailable.)

I noticed that @kib introduced support for Mikrotik 10/25G NIC via commit 77b637338a36 . So probably it is too aggressive to disable MSI-X totally.
I do not use alc(4) but I support you to disable MSI-X only on AR8171 and Killer devices.

i am not 100% convinced this is a hardware problem since Linux appears to enable MSI-X by default, but either way it doesn't work.

A quick search with the key words "ar8171 msix" shows that there's an old report [1] about the MSI-X issue with Linux driver. I have not looked into the Linux driver sources so I'm not sure whether it is still valid or not.

[1] https://www.linuxquestions.org/questions/linux-hardware-18/problem-with-onboard-ethernet-adapter-4175597014/