looks like this is in fact somehow related to laptop-mode-tools / r8169 misbehaves if shut down.
In the end it is enough to shut down the interface via: ip link set dev eth0 down to produce the errors messages: [90830.764253] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90830.840253] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90830.915939] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90830.991631] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.068731] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.135730] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.211712] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.286904] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.459953] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.535702] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). [90831.611131] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). ... but in this case the errors stop if one brings up the interface again via: ip link set dev eth0 up Jan 26 11:02:00 amalthea kernel: [90937.282145] r8169 0000:02:00.0 eth0: rtl_counters_cond == 1 (loop: 1000, delay: 10). Jan 26 11:02:00 amalthea avahi-daemon[2719]: Joining mDNS multicast group on interface eth0.IPv4 with address 192.168.5.2. Jan 26 11:02:00 amalthea kernel: [90937.349408] r8169 0000:02:00.0 eth0: link down Jan 26 11:02:00 amalthea kernel: [90937.350428] IPv6: ADDRCONF(NETDEV_UP): eth0: link is not ready Jan 26 11:02:00 amalthea avahi-daemon[2719]: New relevant interface eth0.IPv4 for mDNS. Jan 26 11:02:00 amalthea avahi-daemon[2719]: Registering new address record for 192.168.5.2 on eth0.IPv4. Jan 26 11:02:01 amalthea ntpd[2861]: Listen normally on 61 eth0 192.168.5.2 UDP 123 Jan 26 11:02:01 amalthea ntpd[2861]: peers refreshed don't know what exactly happens in the suspend case but maybe the interface is shut down and never brought back up again because no cable is connected
