Desktop/Whiteboards/DockingStations

The desktop needs to be aware of the docked/undocked status of the laptop and react appropriately to changes. One important part of this is that X needs to detect monitors and configure them in a useful way, without any need for the users to initiate that manually.

From a recent irc discussion:

<mclasen> hey, I have a fun question
<jkkm> ruhroh.
<jkkm> :)
<mclasen> docking stations...do we get any dock/undock notifications from the kernel nowadays ?
<jkkm> should get pci express hotplug events, and possibly an acpi event, but i'm not sure if there's anything explicit.
<mclasen> basically wondering if it would be doable to make X detect monitors when you dock/undock
<jkkm> oh. ooh.
<mjg59> mclasen: Yes
<mjg59> There's an ACPI event fired. There's also SW_DOCK, which is more generalisable - it'll also be fired on some non-ACPI docks
<jkkm> ah, good, i'm glad you showed up. sorry, i got lost in bugmail. :/
<mjg59> However, SW_DOCK broke the ACPI docking code
<mjg59> So I need to fix that
<mjg59> mclasen: For added fun, some (and I do mean some) systems will fire an ACPI video change notification, so you'll get a KEY_SWITCHVIDEOMODE (or whatever) already
<mjg59> Which probably means that you'll need some debounce
<mclasen> sounds like the average 'who handles this key/event' confusion...
<mjg59> Yeah.
<mjg59> mclasen: The way I'd assumed this would work would be that we'd have implicit docked and undocked profiles
<mjg59> And dock/undock would switch you between them
* rtcm has quit (Leaving.)
<mclasen> sounds reasonable
<mjg59> So remember the docked state separately from the undocked one
<mjg59> But never show them separately in the UI