Making Fedora work with laptops on docking station with external monitor

Pasi Kärkkäinen pasik at iki.fi
Sun Oct 3 13:24:32 UTC 2010


Hello,

I just tried Fedora 14 Beta LIVE CD and noticed things are still problematic
on my setup:

- Laptop with radeon graphics
- Attached to a docking station with external (DVI) monitor.

The lid of the laptop is closed when the laptop is in the docking station, 
so only the external monitor is in use.
Internal LVDS display should not be used at all in this case.

Now what happens when Fedora 14 Beta boots up:

- I can see the BIOS, grub and kernel booting up on the external monitor.
- when GDM starts the external monitor goes blank/black !!
- If I open the (closed) laptop LID I can see the internal LVDS display
  is enabled and GDM login prompt is there !!

I was tracking this down, and it happens probably because the internal LVDS
is always reported as 'connected' by the radeon driver, so it gets enabled
even when the laptop lid is closed. The radeon/drm driver maintainer (Alex Deucher)
confirmed this is not a bug, that's how it's designed to be, and the "policy"
of enabling/disabling outputs is left to userspace! 

So, some component in userspace should check the ACPI lid state and based
on that enable/disable the internal LVDS.

On my laptop ACPI lid state works just fine:
$ cat /proc/acpi/button/lid/LID/state
state:      open

or closed, depending if the lid is actually open or closed.

So the question is which userspace component should be taking care of
disabling the internal LVDS when the laptop lid is closed?

- plymouth
- GDM
- Xorg
- gnome-power-manager
- something else?

Please let us know what you think of this.. This behaviour is very problematic
for laptop users who use docking stations, so it would be very nice to get
this resolved.. There are many bug reports about this problem on Fedora bugzilla
for various Fedora versions.


Some bugzilla entries about/related to this problem:

"internal LCD under the closed lid used as primary display":
https://bugzilla.redhat.com/show_bug.cgi?id=595644

"KMS forcing LVDS laptop display active with lid closed":
https://bugzilla.redhat.com/show_bug.cgi?id=539180

"External monitor output is switched off when closing the laptop lid":
https://bugzilla.gnome.org/show_bug.cgi?id=589736

"Gnome power manager suspends system when notebook in docking station is closed."
https://bugzilla.redhat.com/show_bug.cgi?id=598540

"maybe we shouldn't suspend on lid close if using external inputs and outputs":
https://bugzilla.redhat.com/show_bug.cgi?id=546497


Thank you!

-- Pasi



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