This post is a redirection from : https://support.steampowered.com/view.php?ticketref=5578-QYUD-2478

Hi, thanks for supporting Linux that's great!

I found a little problem with steam's dependencies with xserver-xorg-lts-saucy package.
This package is made by canonical for long time support hardware policy.

And it install a fresh version of X11 and graphic libraries which are distributed with X such as libgl1-mesa-glx:i386 and libgl-mesa-dri:i386.

But as you use xserver-xorg-lts-saucy, the two listed lib broke several dependencies from X11.

I find a way to solve this problem
this need me to install : libgl1-mesa-glx-lts-saucy:i386 and libgl1-mesa-dri-lts-saucy:i386 to resolve steam dependencies and dodge a broken package architecture.

ps : Thanks for your work and community policy around SteamOS that's a very nice thing to work with the Linux community and not against. :)

Thing to do to reproduce this bug :

# This bug was found on a up to date ubuntu12.04.04.
$> sudo apt-get update && sudo apt-get dist-upgrade 

$> sudo apt-get install linux-generics-lts-saucy linux-image-generics-lts-saucy \
linux-header-generics-lts-saucy

# update kernel
$> sudo apt-get install --purge xserver-xorg-lts-saucy

# if there is any problem with nvidia or amd dkms modules...
# Reinstall + purge it. (I was obliged to do it...)
# Launching steam :
$> steam

# This pop a term for installing two missing dependancies of steam :
# libgl1-mesa-glx:i386 libgl-mesa-dri:i386.
# And I cannot do it without package breakage.

# This solve it for me :
$> sudo apt-get install libgl1-mesa-glx-lts-saucy:i386 \
libgl1-mesa-dri-lts-saucy:i386