Let me offset that with a different view: I have bought 4[1] different laptops over the past month, running Ubuntu 12.04 on them. One of my key tests was plugging in my external HDMI monitor, in which it worked for all of them.
In all seriousness, if this is happening to you send me a private message and we can look over your specs and dig into what could be causing it.
[1] HP Envy 15 3033, Acer S3, Asus TimelineX, Macbook Pro
In all seriousness, if this is happening to you send me a private message and we can look over your specs and dig into what could be causing it.
[1] HP Envy 15 3033, Acer S3, Asus TimelineX, Macbook Pro