[ltp] Question on X60

[Henrique de Moraes Holschuh]

On Thu, 01 Mar 2007, Alex Deucher wrote:
> both crtcs.  I'm not sure all bioses support this.  the optimal
> solution would be to just run xrandr when you receive an acpi event.
> Then the X driver can handle the events natively.  On another note,

Yes.  There is a very wide misconception about how ACPI and video switching
is supposed to work.  A quick read of the ACPI v3.0a specs will make it very
clear: ACPI informs whatever is running (the framebuffer, or X) *what*
output the user is requesting to be enabled.  Something else than ACPI (i.e
framebuffer or X) does the switching.

Too bad we don't usually get the proper spec sheets to implement these
things on X and the kernel, huh?

ACPI BIOS-driven switching is a *legacy* thing, and it is expected to be
disabled by any OS doing something more serios to the video hardware than
text mode display.  Which means the X drivers and framebuffer drivers have
to know how to poke the hardware to enable this-and-that output.

ibm-acpi actually does some dubious stuff (i.e. it attempts to re-enable
ACPI video switching temporarily) to attempt to cause video switchs.  I am
not confortable with that code, and might well rip it out in a not too
distant future.  If something disabled video switching, it will remain
disabled.  It is much better to be upfront about not being able to support
something than to do gross hacks that don't work 90% of the time.

-- 
  "One disk to rule them all, One disk to find them. One disk to bring
  them all and in the darkness grind them. In the Land of Redmond
  where the shadows lie." -- The Silicon Valley Tarot
  Henrique Holschuh