[PATCH evdev] Export device node as property.

[Dan Nicholson]

On Fri, Feb 4, 2011 at 6:24 AM, Peter Korsgaard <jacmet at sunsite.dk> wrote:
>>>>>> "Dan" == Dan Nicholson <dbn.lists at gmail.com> writes:
>
> Hi,
>
>  >> The question is perhaps what the use case for this property is? To
>  >> easily figure out what xinput id corresponds to a config entry in
>  >> xorg.conf? The reason I wanted the property was slightly different. As
>  >> the xinput ids are not stable, I wanted a stable identifier so I can
>  >> reapply xinput settings at login time (E.G. for the coordinate
>  >> transformation matrix for multihead touchscreens) through
>  >> gnome-settings-daemon, similar to how it does for the xrandr setup.
>
>  Dan> Maybe another property is needed to satisfy that. What about "Device
>  Dan> UID", which is string setup by the driver. On evdev, it uses
>  Dan> EVIOCGPHYS, but it's up to the driver since it has the most details
>  Dan> about the device.
>
> That's fine by me as well.
>
>  Dan> I still think "Device Node" is useful, but I see your point about
>  Dan> needing a unique identifier. Then gnome-settings-daemon can look
>  Dan> at the combination of DISPLAY hostname and "Device UID" to know
>  Dan> which cached settings to grab.
>
> What is the use case about 'Device Node'? Purely informational like I
> mentioned above, or is there another need for it?

I think informational, but as Peter H. mentioned, mapping from xinput
output to actual device node can be pretty useful. Arguably if you
have EVIOCGPHYS, you can look in /proc/bus/input/devices and map back
to device node, but I think what people typically want is the device
node.

--
Dan