Ubuntu – Network connection error after suspend Ubuntu 14.04

Solution worked for me (copied from my personal manuals without modification). I've got Lenovo T530 with Ubuntu 14.04; mainline kernel 3.14.9; nvidia-331-updates package installed (331.38-0ubuntu7).

=> suspend/resume works for me quite well. => I was solving also problem with resume after hibernation, and the solution: eject SD card from the laptop! :-|

My comments that worked for me (some months ago):

suspendResume_WORKING() {
# WIFI solution
# 1.) sudo vi /etc/pm/config.d/modules
# 2.) Replace SUSPEND_MODULES with this line:
#         SUSPEND_MODULES="$SUSPEND_MODULES uhci_hd button ehci_hd iwlwifi"

# SD card solution:
# 3.) Copy file from https://github.com/wschaub/T530-    settings/blob/master/pm/sleep.d/unmount_sdcard
#     to /etc/pm/sleep.d/unmount_sdcard
# 4.) chmod +x /etc/pm/sleep.d/unmount_sdcard

# ACPI solution:
# 5.) Replace lines in /etc/default/grub
#     GRUB_CMDLINE_LINUX_DEFAULT="noquiet nosplash acpi_osi=Linux acpi_backlight=vendor acpi_sleep=s4_nohwsig loop.max_part=63 loop.max_loop=64"
#     GRUB_CMDLINE_LINUX=""


# X.) sudo update-initramfs -u
# X+1.) sync; sudo reboot

}

Lifted from Wifi doesn't work after suspend after 16.04 upgrade

I found that first researching which ethernet hardware and driver/module I am running, and then removing and reloading that module, did work for me (though it did not for buzhidao):

Wifi:

$ lspci -knn | grep Net -A2

Ethernet:

$ lspci -knn | grep Ether -A2

The second of these (ethernet) was what I used, and I found:

03:00.0 Ethernet controller [0200]: Realtek Semiconductor Co., Ltd. RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [10ec:8168] (rev 0c)
        Subsystem: Hewlett-Packard Company RTL8111/8168/8411 PCI Express Gigabit Ethernet Controller [103c:1944]
        Kernel driver in use: r8169
        Kernel modules: r8169

so i reloaded the 'r8169' driver:

$ sudo rmmod r8169 && sudo modprobe r8169

and voila! This worked. My ethernet port / connection came back alive (after suspend/wakeup) without having to reboot.

in my case the driver was different, but the same commands rmmod and modprobe did the trick