Re: [REGRESSION 6.16] r8169 RTL8168h/8111h fails to probe — "Unable to change power state from D3cold to D0" — bisected to 4d4c10f763d7

On 6/12/26 03:07, Josh Perry wrote:
> #regzbot introduced: 4d4c10f763d7
> 
> Since v6.16 one of two onboard RTL8168h/8111h NICs on this board fails
> to probe on boot; the device drops to D3cold and the driver can't bring
> it back:

FWIW, that commit is 4d4c10f763d780 ("PCI: Explicitly put devices into
D0 when initializing") [v6.16-rc1] from Mario, who is already CCed, but
looks like might be on holiday or something due to inactivity on the
lists in the recent days. So it might take a few days before this moves on.

Josh, this is not my area of expertise, but there are two things I guess
might be helpful:

* retry with 7.1
* upload "dmesg" and "sudo lspci -vvv" output from working and broken
kernels somewhere (like bugzilla.kernel.org).

Ciao, Thorsten

>   r8169 0000:02:00.0 eth0: RTL8168h/8111h, 00:2b:67:48:40:01, XID 541,
> IRQ 137
>   r8169 0000:04:00.0: Unable to change power state from D3cold to D0,
> device inaccessible
>   r8169 0000:04:00.0: Mem-Wr-Inval unavailable
>   r8169 0000:04:00.0: error -EIO: PCI read failed
>   r8169 0000:04:00.0: probe with driver r8169 failed with error -5
> 
> The board has two identical RTL8168h NICs (both XID 541): 0000:02:00.0
> and 0000:04:00.0. Only 04:00.0 fails — its sibling 02:00.0, on a
> different root port, probes and works normally on the very same kernel
> and boot. The failing NIC then does not appear (no enp4s0), taking the
> machine's WAN offline. This strongly suggests the problem is port/
> topology-specific rather than device- or driver-specific: the upstream
> port behind 04:00.0 is placed in D3cold and the endpoint cannot be
> resumed to D0.
> 
> Hardware: RTL8168h/8111h, XID 541, PCI 04:00.0 (onboard 1GbE).
> Platform: Lenovo ThinkCentre M90n-1 (11AHS0B200), BIOS M2AKT49A
> (2026-03-25, latest available). Firmware is current, so this is not a
> platform-firmware issue.
> 
> Bisection: v6.15 good, v6.16 bad (verified by booting both). I then
> reverted 4d4c10f763d7 ("PCI: Explicitly put devices into D0 when
> initializing") together with its follow-up 907a7a2e5bf4 ("PCI/PM: Set up
> runtime PM even for devices without PCI PM") on top of 6.16.7: the NIC
> probes and links at 1Gbps/Full normally, with no workaround:
> 
>   r8169 0000:04:00.0 eth1: RTL8168h/8111h, 00:2b:67:48:40:02, XID 541,
> IRQ 138
>   r8169 0000:04:00.0 enp4s0: Link is Up - 1Gbps/Full - flow control rx/tx
> 
> Workaround: booting an unmodified v6.16+ kernel with pcie_port_pm=off
> also restores the NIC, which is consistent with the upstream port being
> placed in D3cold and the device failing to resume to D0 after the
> explicit-D0 init change.
> 
> The follow-up 907a7a2e5bf4 does not fix this resume case: v6.18.33 is
> still affected (retested today on current firmware).
> 
> Happy to test patches or provide full dmesg / lspci.
>