Dell Studio XPS 1640: WiFi doesn't start after resume from suspend mode

[cbiz8]

I've installed Saucy, everything works fine so far, but WiFi doesn't start after resume from suspend mode.
KDE 4.10.7 Kernel 3.10.0-6-generic.
Thanks in advance

[GreyGeek]

That's a bug. More than likely if you open the Network Manager in the system tray it will tell you that "Network Manager is unmanaged"
Use
kdesudo kate
and open
/etc/NetworkManager/NetworkManager.conf
and see if it has the section

[ifupdown]
managed=false

If it does change it to 'true', which tells KNetworkManager to manage the networking.
Then make sure the "Enable Networking" checkbox is checked, and the wireless too, if you are using it.

Another condition related to this is the possibility that the network itself is down, which has nothing to do with KNetworkManager.

The file /var/lib/NetworkManager/NetworkManager.state

[main]
NetworkingEnabled=true
WirelessEnabled=false
WWANEnabled=true
WimaxEnabled=true

and "NetworkingEnabled=false" will disable the network. It it using "kdesudo kate" and change false to true.

[cbiz8]

GreyGeek, thanks for your reply. I changed "managed=true" and, after rebooting, it worked one time, the next times i couldn't went to the suspend mode, even shutting down WiFi before. I tried this twice, same issue. The NetworkManager was Ok, all the 4 items =true.
I tried this too, unsuccesfully

2. The next step is to edit the /etc/pm/config.d/unload_modules file as root with a text editor:

sudo kate /etc/pm/config.d/unload_modules


(the file may not exist in which case, an empty file will come up - that's ok)

And inside this file, paste the following line:

SUSPEND_MODULES="$SUSPEND_MODULES MODULE_NAME_FOUND_UNDER_STEP_1"

replacing "MODULE_NAME_FOUND_UNDER_STEP_1" with the Kernel module name for your network interface found under step 1, "r8169" in my case.

Example:

SUSPEND_MODULES="$SUSPEND_MODULES r8169" (in my case "iwlwifi")

[sithlord48]

does your laptop have a switch to turn the wifi on / off . if it does you may need to re enable the wifi this way before being able to use the wifi after sleep . i once had a laptop with a similar issue like this for the bluetooth , eventually the issues was fixed by some update.

[cbiz8]

sithlord48: after changing "managed=true", the laptop doesn/t suspend anymore, even if i switch the WiFi Off. Thanks for your concern.

[GreyGeek]

Suspending has a bug which fails to resent NetworkManager's "manged=false" to "managed=true" when awakened. Ergo, don't use suspend if your hardware is affected

[cbiz8]

Thank you, GreyGreek.
Is this a Kernel Bug?
With a hope off solution?

[SteveRiley]

It's a lack-of-documentation bug; a no-standard-sleep-mechanism bug. There is no consistent, standard mechanism for sleeping and resuming. Each manufacturer has its own quirks, and there exist variations within quirks too. Not much we can do about it, I'm afraid.

[cbiz8]

Ok, thank you, SteveRiley.
If i have trouble with Kubuntu that it means i'll have trouble with all KDE based distribution?
Or perhaps with all Linux Distribution?
I mean with this Dell Studio XPS 1640.

[SteveRiley]

This is a general Linux problem. Hardware manufacturers provide scant details about their various mechanisms for handling power control. ACPI is not well documented and most implementations are buggy.

[GreyGeek]

What Steve said. I've seen similar reports for all distros based on Ubuntu, and for Fedora and SUSE as well, running Gnome and KDE. Haven't seen it for the lite desktops, though.

One of the couple dozen people I support had this problem when she inadvertently put her laptop to sleep instead of turning it off. (Don't ask, I don't know how she did it!) While researching that and another problem I noticed that some laptops were also giving Win7 a rough time with failures to activate the wifi after waking up and also with disconnects and reconnects, but my Win7 side doesn't exhibit the problem as far as I can tell. However, in the last 18 months I've booted into my Win7 side about once every 6 months to update it, but I never run it for anything or keep it running after the updating is done.

When I changed the "managed=false" to true it restored Network-Manager functionality. I found it was reproducible and advised her to not use sleep or hibernate.