After suspend, steam client freezes on startup but works again after a reboot

Steam works fine but it hangs when I apply the following steps:

1. Start steam
2. Stop steam
3. suspend my laptop
4. (after wakeup) start steam

Now the steam client hangs at startup. I only see a blank popup window without any content. I assume that should be the login popup ("Connecting to steam account").

The only workaround is to reboot my system. If I try killall steam && steam, it still hangs again at the same point.

Here is the console output:

Running Steam on ubuntu 14.10 64-bit
STEAM_RUNTIME is enabled automatically
[2015-01-02 16:06:15] Startup - updater built Nov 21 2014 16:23:41
Looks like steam didn't shutdown cleanly, scheduling immediate update check
[2015-01-02 16:06:15] Checking for update on startup
[2015-01-02 16:06:15] Checking for available updates...
[2015-01-02 16:06:16] Download skipped by HTTP 304 Not Modified
[2015-01-02 16:06:16] Nothing to do
[2015-01-02 16:06:16] Verifying installation...
[2015-01-02 16:06:16] Performing checksum verification of executable files
[2015-01-02 16:06:17] Verification complete
Requested Force create but SharedObjectMutex already created
Forced create but already created for SharedObjectEvent
Forced create but already created for SharedObjectEvent

--- here it hangs. After a reboot, it would continue like that ---

Running Steam on ubuntu 14.10 64-bit
STEAM_RUNTIME has been set by the user to: /home/phil/.steam/ubuntu12_32/steam-runtime

Here is the output of ~/.steam/error.log:

rm: cannot remove ‘/home/phil/.steam/steam’: Is a directory
rm: cannot remove ‘/home/phil/.steam/bin’: Is a directory
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
Gtk-Message: Failed to load module "overlay-scrollbar"
Gtk-Message: Failed to load module "overlay-scrollbar"
Installing breakpad exception handler for appid(steamwebhelper)/version(20141121162341)
Installing breakpad exception handler for appid(steamwebhelper)/version(1416587021)
Installing breakpad exception handler for appid(steamwebhelper)/version(1416587021)
Installing breakpad exception handler for appid(steamwebhelper)/version(20141121162341)
Installing breakpad exception handler for appid(steamwebhelper)/version(1416587021)
[0102/162746:ERROR:nss_util.cc(1018)] Failed to load NSS libraries.
Installing breakpad exception handler for appid(steam)/version(1416617579)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
FillInMachineIDInfo took a total of 0 milliseconds
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
Installing breakpad exception handler for appid(steam)/version(1416617579)
Generating new string page texture 2: 48x256, total string texture memory is 49,15 KB
Generating new string page texture 3: 256x256, total string texture memory is 311,30 KB

I tried several recommended workarounds, for example:

• killall steam && rm ~/.steam/steam/appcache
• mv /etc/fonts/conf.d/10-scale-bitmap-fonts.conf{,.BAK}

However, only a reboot fixes the start problem.

I'm using Ubuntu 14.10 (64-bit). (My window manager is i3. Don't think that is relevant but I read about issues with xmonad.)