Laptop doesn't know which display to use when docked.

[David G. Miller]

Terry Polzin <foxec208 <at> wowway.com> writes:

> 
> I am running xfce on F17 completely patched and current.
> 
> My laptop is a HP probook 6460b.  When I boot it docked the grub screen
> appears on the external display.  When the boot has completed the
> background screen is displayed on the external display. I get no login
> prompt on the external display.  I press enter a couple of times the
> login display will appear and I'll log in then the external display goes
> dark.  I open up the laptop and it's display has the desktop on it and I
> have to manually switch to the external display and discontinue use of
> the laptop display.  If both displays are selected for use the whole
> thing wants to act like a twin head setup which I don't want.
> 
> What do I have to do to get the laptop to use the external display when
> docked and it's own display when it isn't automagically. To undock the
> laptop I have to reverse the display procedure of course.  This also
> makes it impossible to "undock and run" without making manual changes as
> to which display to use.
> 

I had the opposite problem.  When I am at work I run my laptop in dual head
mode.  If I'm travelling, I just have the laptop.  The laptop (HP Pavilion G7)
seemed to think that the external monitor was always attached and would not
switch to just the internal display.  This is with FC-16 and xfce.

My first work-around was to boot in graphical mode.  All I had to do was wait
until the system had put up the login screen and then I could hit the screen
brightness (brighter) adjustment button a few times and there was my login
screen.  Hitting the button prior to X starting had no effect (good or bad). I
had a completely black screen until X was up and then I could adjust the
brightness.  Likewise, the system would only use the external monitor, if
attached, while booting but, since I could see the boot progress on it, I knew
when I could adjust the brightness of the laptop's internal monitor.  Also, the
display select button had no effect.

I did some digging and finally found a bug report that mentioned setting a
couple of kernel parameters: acpi_backlight=vendor acpi_osi=linux
video.brightness_switch_enabled=1.  You might try playing with these to see if
they have any affect on your issue.

Cheers,
Dave