Hello all,

For the past few versions of Ardour 3 on the versions 13.10 and 14.04 (Alpha2) of Ubuntu, I still needs to use export FORCE_BUGGY_GRADIENTS=1 before running Ardour otherwise the GUI is sluggish. It is important to note that I’m running the open source radeon driver from the kernel 3.13.

I think I have always had to set the variable since Ardour 3, I simply forgot about it until I re-installed my laptop and was reminded with a slow GUI that it had to be done.

I was curious to find out what was the status of the issue. From a bit of googling:

  • It hasn’t been mentionned for a while on the Ardour forum
  • The last update was that it was impacting only proprio NVidia or Radeon drivers

Are people around experiencing the same thing?

If is just a well known fact, it would be good to have it documented here so other Ardour users might easily find it when googling around :slight_smile: (and as I’m writing that, I really really that it is not already documented - I just looked again and couldn’t find a definitive note on the topic).


what cpu governer are you using.

I have had problems with sluggish gui which i thought to be a buggy graphics driver, however recently i have found that when using the ondemand cpu governer i get sluggish gui but if i switch to performance the issues go away.

you can change the cpu governer with this

sudo apt-get install indicator-cpufreq

you should now have an applet on your taskbar that will allow you to change the governer from ondemand to performance

Thanks for the info, I’m already using the Performance governer.

The part of the GUI that is particularly improved by setting the FORCE_BUGGY_GRADIENTS are the View Meters.
When using Ardour yesterday on the same session, I could really see the difference:

  • Run Ardour -> GUI/VUs are slow
  • Set FORCE_BUGGY_GRADIENTS and run Ardour -> GUI/VUs are very responsive

blablack: welcome to The Club Of People Using Way Old And Broken Video Drivers. I am the club president, and I am happy to see you as a new member.

paul: that’s sad - that’s the brand new 3.13 kernel with the brand new open-source radeon driver!

Ok, so to confirm (and for those landing here from a Google search) -> sluggish Ardour GUI can be fixed by an easy export FORCE_BUGGY_GRADIENTS=1 before starting Ardour, and it does impact NVidia/Radeon both closed and open-source drivers.

we’ll brand new upto to the minute just out stuff tends to be, well full of bugs.

they bring out new features, change how the code is implemented which then breaks stuff that was previously working, so developers then have to redo stuff that was working before.

I tried kernel 3.11 and found it to be a step back. whatever changed in the kernel on my system causes more x runs. with the same project on 3.8 kernel i dont get x runs, on 3.11 tons of x runs.

if that macro works, it implies that there is a bug in the video driver/XRender stuff when it comes to rendering gradients, and that telling Cairo to do itself on the CPU is actually faster. It needs to be pushed to the video driver/XRender crowd (possibly for your distro).