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I recently upgraded to Oneric and found that Fn+F8 does not switch displays on Oneric, Dell E6410, Nvidia. I frequently run presentations and need to switch between projector and laptop with minimum fuss, so this key is important to me!

In Maverick, I managed to make it work using acpi_osi=\\\"!Windows 2009\\\" in grub (as described here: It's a bit shameful to go into a room of people, plug the laptop and wait 5 minutes to make the change using nvidia-settings. How can I make the Fn+F8 work again?

After a bit of debuging with xev it seems that the acpi_osi has some effect but the videoswitch does not take place somewhere else even if /var/log/XOrg.0.log shows:

[ 24182.812] (II) PM Event received: Capability Changed

Maybe there is some other place where the event is not handled correctly.

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Try going to the system/power cog and clicking displays. From there you can switch your displays quickly. – William Nov 6 '11 at 22:48
William, I think this does not work if using the Nvidia driver; in that case you have to use nvidia-settings. disper and the disper-indicator could be a viable workaround, that's what I do. – Christoph Nov 9 '11 at 15:13

Finally I gave up and decided to adopt the simpler solution of using disper.

apt-add-repository ppa:disper-dev/ppa
apt-get update
apt-get install disper

and then

disper -c to switch to external monitor and disper -s to return to main screen. I also configured a shortcut in xfce which I now use to map p to disper -c

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Better solution for me seems to be to switch external display on/off using nvidia-settings, where it is possible to detect resolution of external display and switch the TwinView feature on and off (as well as other helpful configuration options).

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This post worked for me on a Dell Precision M6600 Ubuntu 14.04. Fn+F8 was broken

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Did it work in Windows? It may be that you are using the wrong key. Also, try using other keys (eg Fn+F5, Fn+F9, etc)

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its clear that the user knows what key to use and they were working before the upgrade. – Bruno Pereira Nov 10 '11 at 11:17

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