[systemd-devel] Alienware graphics amplifier scancodes

Greg KH gregkh at linuxfoundation.org
Thu May 28 11:26:52 PDT 2015

On Thu, May 28, 2015 at 06:48:49PM +0200, Lennart Poettering wrote:
> On Wed, 27.05.15 15:59, Mario Limonciello (mario_limonciello at dell.com) wrote:
> > Hi,
> > 
> > Some Alienware notebooks and desktops support an external graphics
> > housing called the "Alienware Graphics Amplifier". It allows the usage
> > of a larger or more modern graphics card than your gaming PC would
> > already support.  In order to provide a good experience, systems that
> > support it can provide notification to the OS via the scancodes on the
> > the keyboard controller of events related to the cable.
> > 
> > The following 4 events are supported (and the presumed OS response):
> > * Cable plugged in (An app on the existing display or terminal would
> > tell the user to reboot the system to activate)
> > * Undock cable pressed (An app would let the user know to reboot the
> > system to complete undock process; also when supported by GFX driver,
> > driver can clean up and work without a reboot)
> > * Undock hotkey pressed (Same result as undock cable expected)
> > * Surprise removal of cable (System immediately reboots).
> > 
> > The first three events I think it would make sense to assign to a
> > keycode that a userspace application in X land can pickup and recognize,
> > but I'm at a loss what makes most sense (prog1, prog2, prog3 maybe?).
> > This userspace application hasn't yet been made or decided, I just want
> > to pave the path for it first.
> > 
> > The fourth event I'm submitting a kernel patch
> > (https://lkml.org/lkml/2015/5/27/817) so that the kernel would issue a
> > reboot when this was detected, so I believe it would  make sense to mark
> > it 'unknown' in systemd.
> > 
> > Also, these don't show up in xev output, but they do show up in evtest.
> > 
> > Can I get some advice on these?  I'll gladly submit a bug with a patch
> > afterward.
> You are aware that the kernel has PCI hotplug support? It sounds
> really weird rebooting the machine due to hotplug events. That's not
> how these things are done... 
> Are you sure the kernel folks would be happy with a patch that
> chickens out and instead of proper PCI hotplug just always reboots?

We are not happy with such a thing at all, I'll go respond to that
kernel patch now, this is not an acceptable solution in any way.

greg k-h

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