[REGRESSION] r8169: RTL8168h "transmit queue 0 timed out" after ASPM L1 enablement

[Bernhard Hampel-Waffenthal <bernhard.hampelw@posteo.at>]

#regzbot introduced: 4b5f82f6aaef3fa95cce52deb8510f55ddda6a71

Hi,

since the last major kernel version upgrade to 5.18 on Arch Linux I'm 
unable to get a usable ethernet connection on my desktop PC.

I can see a timeout in the logs

 > kernel: NETDEV WATCHDOG: enp37s0 (r8169): transmit queue 0 timed out

and regular very likely related errors after

 > kernel: r8169 0000:25:00.0 enp37s0: rtl_rxtx_empty_cond == 0 (loop: 
42, delay: 100).


The link does manage to go up at nominal full 1Gbps speed, but there is 
no usable connection to speak of and pings are very bursty and take 
multiple seconds.

I was able to pinpoint that the problems were introduced in commit 
4b5f82f6aaef3fa95cce52deb8510f55ddda6a71 with the enablement of ASPM 
L1/L1.1 for ">= RTL_GIGA_MAC_VER_45", which my chip falls under. Adding 
pcie_aspm=off the kernel command line or changing that check to ">= 
RTL_GIGA_MAC_VER_60" for testing purposes and recompiling the kernel 
fixes my problems.


I'm using a MSI B450I GAMING PLUS AC motherboard with a RTL8168h chip as 
per dmesg:

 > r8169 0000:25:00.0 eth0: RTL8168h/8111h, 30:9c:23:de:97:a9, XID 541, 
IRQ 101

lspci says:

 > 25:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. 
RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] 
(rev 15)
         Subsystem: Micro-Star International Co., Ltd. [MSI] Device 
[1462:7a40]
         Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- 
ParErr- Stepping- SERR- FastB2B- DisINTx+
         Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- 
<TAbort- <MAbort- >SERR- <PERR- INTx-
         Latency: 0, Cache Line Size: 64 bytes
         Interrupt: pin A routed to IRQ 30
         IOMMU group: 14
         Region 0: I/O ports at f000 [size=256]
         Region 2: Memory at fcb04000 (64-bit, non-prefetchable) [size=4K]
         Region 4: Memory at fcb00000 (64-bit, non-prefetchable) [size=16K]
         Capabilities: <access denied>
         Kernel driver in use: r8169
         Kernel modules: r8169


If you need more info I'll do my best to provide what I can, hope that 
helps already.

Regards,
Bernhard