Ethernet Master/Slave resolution failed +oops

I have an old Asus laptop which works fine as a print server, and I want to connect it to my LAN using Ethernet.
But the link stays down and dmesg shows a kernel crash.
Wifi works correctly.

I’m using 20.03.3101.0d0660fde3b (Markhor) with NetworkManager,
and here is the relevant output from dmesg:

[   51.790230] RTL8211DN Gigabit Ethernet r8169-500:00: attached PHY driver [RTL8211DN Gigabit Ethernet] (mii_bus:phy_addr=r8169-500:00, irq=IGNORE)
[   52.004393] r8169 0000:05:00.0 enp5s0: Link is Down
[   52.020904] iwlwifi 0000:03:00.0: Radio type=0x0-0x0-0x3
[   52.076902] iwlwifi 0000:03:00.0: Radio type=0x0-0x0-0x3
[   52.131928] iwlwifi 0000:03:00.0: Radio type=0x0-0x0-0x3
[   52.189236] iwlwifi 0000:03:00.0: Radio type=0x0-0x0-0x3
[   53.941882] NET: Registered protocol family 17
[   54.628924] iwlwifi 0000:03:00.0: Radio type=0x0-0x0-0x3
[   54.686441] iwlwifi 0000:03:00.0: Radio type=0x0-0x0-0x3
[   55.104156] wlp3s0: authenticate with d4:6e:0e:36:f2:7d
[   55.108176] wlp3s0: send auth to d4:6e:0e:36:f2:7d (try 1/3)
[   55.110486] wlp3s0: authenticated
[   55.111468] wlp3s0: associate with d4:6e:0e:36:f2:7d (try 1/3)
[   55.116050] wlp3s0: RX AssocResp from d4:6e:0e:36:f2:7d (capab=0x431 status=0 aid=2)
[   55.124720] wlp3s0: associated
[   56.208025] IPv6: ADDRCONF(NETDEV_CHANGE): wlp3s0: link becomes ready
[   69.226942] RTL8211DN Gigabit Ethernet r8169-500:00: Master/Slave resolution failed
[   69.227000] ------------[ cut here ]------------
[   69.227007] WARNING: CPU: 0 PID: 106 at drivers/net/phy/phy.c:716 phy_error+0xa/0x50 [libphy]
[   69.227007] Modules linked in: ctr ccm af_packet uvcvideo videobuf2_vmalloc videobuf2_memops videobuf2_v4l2 rtsx_usb
wldvm snd_hda_intel snd_intel_nhlt i915 mac80211 libarc4 snd_hda_codec nouveau snd_hda_core intel_rapl_msr intel_rapl_c
ress coretemp intel_gtt crct10dif_pclmul agpgart i2c_algo_bit joydev crc32_pclmul r8169 mousedev ghash_clmulni_intel fb
e_helper iptable_nat nf_nat asus_nb_wmi mxm_wmi asus_wmi input_leds rapl intel_cstate sparse_keymap evdev intel_uncore 
ipv6 nf_defrag_ipv4 libcrc32c wmi button battery ac
[   69.227033]  zram zsmalloc ipt_rpfilter iptable_raw xt_pkttype nf_log_ipv4 nf_log_common xt_LOG xt_tcpudp iptable_fi
intel kvm irqbypass ip_tables x_tables ipv6 crc_ccitt autofs4 ext4 crc32c_generic crc16 mbcache jbd2 rtsx_usb_sdmmc led
ta xhci_pci atkbd libps2 xhci_hcd ehci_pci ehci_hcd scsi_mod usbcore crc32c_intel usb_common i8042 rtc_cmos serio dm_mo
[   69.227055] CPU: 0 PID: 106 Comm: kworker/0:2 Not tainted 5.4.69 #1-NixOS
[   69.227056] Hardware name: ASUSTeK Computer Inc. K53SC/K53SC, BIOS K53SC.216 09/26/2011
[   69.227059] Workqueue: events_power_efficient phy_state_machine [libphy]
[   69.227061] RIP: 0010:phy_error+0xa/0x50 [libphy]
[   69.227062] Code: 03 00 00 31 c9 bf 80 01 00 00 e9 b1 d8 ce e6 90 66 66 66 66 90 eb d9 66 0f 1f 84 00 00 00 00 00 66
[   69.227063] RSP: 0018:ffff9b7ac01ebe38 EFLAGS: 00010286
[   69.227064] RAX: ffff8bf04a4fa940 RBX: ffff8bf03fec1800 RCX: 0000000000000000
[   69.227065] RDX: ffff8bf04a4fa940 RSI: ffff8bf04b6175c8 RDI: ffff8bf03fec1800
[   69.227065] RBP: ffff8bf03fec1c30 R08: ffff8bf04b6175c8 R09: ffff9b7ad00b7a9c
[   69.227066] R10: 0000000000aaaaaa R11: 0000000000000000 R12: ffff8bf03fec1bd8
[   69.227067] R13: ffff8bf03fec1800 R14: 00000000ffffffbd R15: 0ffff8bf04b62dc0
[   69.227068] FS:  0000000000000000(0000) GS:ffff8bf04b600000(0000) knlGS:0000000000000000
[   69.227069] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   69.227069] CR2: 00007f35480015d8 CR3: 0000000044e0a002 CR4: 00000000000606f0
[   69.227070] Call Trace:
[   69.227075]  phy_state_machine+0xf4/0x190 [libphy]
[   69.227078]  process_one_work+0x1eb/0x390
[   69.227080]  worker_thread+0x4d/0x3f0
[   69.227083]  kthread+0xfb/0x130
[   69.227084]  ? process_one_work+0x390/0x390
[   69.227085]  ? kthread_park+0x90/0x90
[   69.227088]  ret_from_fork+0x1f/0x40
[   69.227090] ---[ end trace e5ebcbfcfe0406f7 ]---
[   69.227097] r8169 0000:05:00.0 enp5s0: Link is Down

what could be wrong?

having a search for this, seems there are a number of problem reported with type of chip.

What kernel are you running, it maybe a work around to run and older 4.x kernel, rather than a 5.x one?