Monday, 7 January 2013

Optimus and Ubuntu 12.10

The W530 comes with an integrated intel GPU and a discrete graphics card from nvidia. Out of the box, the firmware is set up to run with Optimus enabled, but it provides option to enable only integrated or only discrete graphics.

I do not want to play any games. This thinkpad is a workhorse. I prefer a very stable system that is able run off battery for an extended duration as I am travelling a lot. I also need to be able to use the external VGA port, I am not so keen on using the mini DisplayPort at the moment.

Stock Ubuntu with Optimus enabled

I started using the laptop with the factory settings as far as graphics setup goes. Between Xmas and New Year's Eve I did not have any chance to test it with an external display, but I confirmed both integrated and discrete graphics are active.

$ lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09)
01:00.0 VGA compatible controller: NVIDIA Corporation GK107 [Quadro K1000M] (rev a1)

Unfortunately, I experienced occasional blank screen on startup - black screen with a X mouse pointer to be precise - that could be worked around by switching to a virtual terminal (e.g. Ctrl-Alt-F1), logging in and restarting lightdm. Also, plymouth failed to show up randomly on startup and shutdown, which was a mostly cosmetic issue, but not a good sign at all. Although this situation was technically manageable, I was looking for a very deterministic, stable configuration, so I changed the firmware settings.

Stock Ubuntu with discrete graphics only

Switched to discrete graphics, which resulted into a garbled screen, an I was not even able to switch to a virtual terminal. This was with the opensource nouveau driver. At that time, I have not tested the proprietary nvidia drivers, but rather quickly changed to integrated graphics in firmware setup.

Stock Ubuntu with integrated graphics only

Switched to integrated graphics, which sometimes worked, but in the majority of case I ended up with an error telling me "The system is running in low-graphics mode". Here, too, I was able to switch to a virtual terminal and recover gracefully. After some investigation it turned out the situation was related to a race condition around lightdm that prevented proper graphical startup - see this bug report for further details. The W530 is up in 4-5 seconds after POST with the fast SSD and is more prone to race conditions therefore.

In the bug report referred to above I found multiple suggested workarounds mainly focused on local scripts restarting lightdm twice. I have applied a slightly different workaround and optimized it to fit my needs:

$ sudo patch /etc/init/lightdm.conf <<EOF
--- /etc/init/lightdm.conf    2012-10-09 17:00:02.000000000 +0200
+++ /tmp/init/lightdm.conf    2013-01-06 00:34:26.061236424 +0100
@@ -42,10 +42,12 @@
         plymouth quit || :
         exit 0

+    # line added to prevent race condition resulting into "The system is running in low-graphics mode"
+    sleep 0.5s
    exec lightdm
end script

post-stop script
     if [ "$UPSTART_STOP_EVENTS" = runlevel ]; then

This tweak introduces negligible delay at startup, and I have not experience any graphics issues ever since. With the discrete graphics card disabled in firmware I was able to run the laptop 12 hours on battery, of which about 3 hours were spent suspended, and the other 9 without heavy workloads, mostly.

There is one very important potential drawback of this approach. On the W530, both the VGA and mini DisplayPort are wired to the nvidia chip - at least this is what I conclude from the user guide and from what I have found on the internet. If this turns out to be the case I will not able to hook up an external display with only the integrated card enabled. This made me unable to use a projector. We'll see once I get access to an external display to test with.

To be continued...

The current writing is the first of a series of posts on the Optimus, W530 and Ubuntu 12.10 tuple. Make sure you do not miss Part 2!


  1. Hi, thank you for posting your installation details. I have a T430s with SSD (Integrated card only) and your posts have been very useful! In particular the first one on the installation on a SSD and this lightdm.conf thing.

    1. I am glad you found it useful, thanks for the feedback.