Custom x86 build with S3 sleep and rtcwake


I have created my own build for x86 and custom kernel, with rtcwake and ACPI support. I have two LAN interfaces and two WLAN interfaces, also using OpenVPN.

The setup is running just fine as AP/router, but I would like to use rtcwake to put computer S3 sleep for overnight. The only problem is that after wake up network connections are not working, also I believe that OpenVPN connection is not re-initialized. After manually restarting openvpn and then network all is good again.

I understand that there are some hacks to make this work (e.g. use watchdog to restart network) but I would like to understand why this is not working out of the box.

Network adapters are (if relevant)
2x Intel Corporation I210 Gigabit Network Connection (rev 03)
2x Qualcomm Atheros QCA9984 802.11ac Wave 2 Wireless Network Adapter