How to run Weston on specific devices?

[me at beroal.in.ua]

Thank you for your answer.

On 05.01.16 10:07, Pekka Paalanen wrote:
> On Tue, 5 Jan 2016 00:08:56 +0200
> me at beroal.in.ua wrote:
>
>> Hello. My computer has 2 seats. By seat I mean a set containing a
>> monitor, a videocard, a mouse, and a keyboard. I can drive them with 2
>> Xorg server, and I am looking for how to replicate this configuration
>> with Wayland.
>>
>> AFAIK, Weston uses "libinput", so I assigned "WL_SEAT" of input devices
>
> Hi,
>
> should that not be ID_SEAT?
>
> Also remember to set it for the DRM device you want to use with the
> seat.
>
> ID_SEAT is for physical seats which is what you are setting up. WL_SEAT
> is for "seats" inside a single Weston session so that you can group
> input devices to different wl_seat Wayland objects. Particularly, two
> mouse devices in the same wl_seat move the same pointer, while two
> mouse devices in different wl_seats gets you two independent pointers
> in the same session.
In fact, this is the thing I don't quite understand. In what situations 
having 2 logical seats inside 1 physical seat is useful? And what seats 
the event "wl_registry::global" announces--logical or physical?

Anyway, I set WL_SEAT and ID_SEAT to "seat1" before writing to this 
list. For example. {{{
$ udevadm info /sys/devices/pci0000:00/0000:00:0d.0/drm/renderD129
calling: info
P: /devices/pci0000:00/0000:00:0d.0/drm/renderD129
N: dri/renderD129
E: DEVNAME=/dev/dri/renderD129
E: DEVPATH=/devices/pci0000:00/0000:00:0d.0/drm/renderD129
E: DEVTYPE=drm_minor
E: ID_FOR_SEAT=drm-pci-0000_00_0d_0
E: ID_PATH=pci-0000:00:0d.0
E: ID_PATH_TAG=pci-0000_00_0d_0
E: ID_SEAT=seat1
E: MAJOR=226
E: MINOR=129
E: SUBSYSTEM=drm
E: TAGS=:seat:seat1:uaccess:
E: USEC_INITIALIZED=13962813
E: WL_SEAT=seat1
}}}

> Have you tried using the --seat command line argument to make Weston's
> DRM-backend pick a seat other than the default "seat0"?
Okay, Weston drives "seat1" if given the option "--seat=seat1" and no 
configuration file. But "seat0" where I start Weston freezes until 
Weston terminates.

Why should I run "weston-launch" from a virtual terminal? I would like 
to run it from "gnome-terminal".

BTW, the option "--connectorid=card1-VGA-2" gives the "unhandled option" 
error.

> You would be running an instance of Weston per each seat / gfx card.
It is an old dream of mine to attach all seats to 1 videocard. Is it 
possible? If not, is this a limitation of Weston, Wayland, or Linux? I 
mean, may 2 processes drive 1 videocard?