How to run Weston on specific devices?

On Tue, 5 Jan 2016 00:08:56 +0200

Post by m***@beroal.in.ua
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.

Post by m***@beroal.in.ua
to "seat1" using "udev" rules according to
http://wayland.freedesktop.org/libinput/doc/latest/udev_config.html . I
run "weston-launch" with a configuration file {{{
[output]
name=card1-VGA-2
seat=seat1
}}}
Weston drives the wrong videocard and the wrong input devices. I see in
its "stderr" that it is scanning all devices.

Have you tried using the --seat command line argument to make Weston's
DRM-backend pick a seat other than the default "seat0"?

You would be running an instance of Weston per each seat / gfx card.

Thanks,
pq

m***@beroal.in.ua

2016-01-05 16:10:23 UTC

Thank you for your answer.

Post by Pekka Paalanen
On Tue, 5 Jan 2016 00:08:56 +0200

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
}}}

Post by Pekka Paalanen
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.

Post by Pekka Paalanen
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?

Peter Hutterer

2016-01-06 01:11:31 UTC

Post by m***@beroal.in.ua
Thank you for your answer.

Post by Pekka Paalanen
On Tue, 5 Jan 2016 00:08:56 +0200

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?

Multi-pointer scenarios, i.e. you want multiple sets of devices
to interact independently on the same display. google for multi-pointer X
for some more info.

Post by m***@beroal.in.ua
And what seats the
event "wl_registry::global" announces--logical or physical?

logical. any device not on the same physical seat won't be visible at all.
so in the example below, if the input devices are all assigned
ID_SEAT=seat1, you won't have any input devices for the seat 0 instance.

Cheers,
Peter

Post by m***@beroal.in.ua
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: USEC_INITIALIZED=13962813
E: WL_SEAT=seat1
}}}

Post by Pekka Paalanen
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.

Post by Pekka Paalanen
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?
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m***@beroal.in.ua

2016-01-06 11:03:02 UTC

Post by Pekka Paalanen
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.

So, what can I do about freezing?

Pekka Paalanen

2016-01-07 08:42:59 UTC

On Tue, 5 Jan 2016 18:10:23 +0200

Post by m***@beroal.in.ua
Thank you for your answer.

Post by Pekka Paalanen
On Tue, 5 Jan 2016 00:08:56 +0200

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: USEC_INITIALIZED=13962813
E: WL_SEAT=seat1
}}}

Peter already replied to the above.

Post by Pekka Paalanen
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.

What do you mean by "freeze"? Black screen? Blank screen? Desktop, but
no reaction to any input? Does the clock update? Got a log from that,
does it open any input devices then?

Post by m***@beroal.in.ua
Why should I run "weston-launch" from a virtual terminal? I would like
to run it from "gnome-terminal".

You cannot run it from X, because the X server is already holding the
DRM master for the gfx card. The X server must release DRM master
before Weston can get it, and you do that by switching away from X's VT
or quitting X. DRM master status is required for controlling KMS
resources by the Weston DRM-backend.

Essentially, this way a random program cannot steal your gfx card away
from your desktop session.

If you want to run Weston from X, use 'weston' which will then open an
X window for Weston and it behaves like any X app, using the X11-backend.

Post by m***@beroal.in.ua
BTW, the option "--connectorid=card1-VGA-2" gives the "unhandled option"
error.

That's because the option is --connector, not --connectorid. The value
is also an integer, not a name.

Post by Pekka Paalanen
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?

It is not possible. It is a limitation of DRM in the Linux kernel. It
does not implement splitting KMS resources of a single device to
several device nodes. A program that opens a device node gets exclusive
control of all KMS resources on that node by becoming "DRM master".
It's all or nothing.

Another solution would be to run a system compositor controlling all
heads, and then running one compositor per seat under the system
compositor. I think this is largely unimplemented in Weston as a system
compositor, though, particularly for the input side.

Thanks,
pq

m***@beroal.in.ua

2016-01-07 10:32:17 UTC

Post by Pekka Paalanen
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.

What do you mean by "freeze"? Black screen? Blank screen? Desktop, but
no reaction to any input? Does the clock update? Got a log from that,
does it open any input devices then?

I run "weston-launch" from a virtual terminal/agetty/login/bash. The
screen does not change, the cursor does not blink. No reaction. I don't
understand what log should I provide.

Post by m***@beroal.in.ua
Why should I run "weston-launch" from a virtual terminal? I would like
to run it from "gnome-terminal".

But I want to run Weston on a gfx card other than X is running on. I
have 2 gfx cards.

Pekka Paalanen

2016-01-07 11:14:37 UTC

On Thu, 7 Jan 2016 12:32:17 +0200

Post by Pekka Paalanen
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.

What do you mean by "freeze"? Black screen? Blank screen? Desktop, but
no reaction to any input? Does the clock update? Got a log from that,
does it open any input devices then?

I run "weston-launch" from a virtual terminal/agetty/login/bash. The
screen does not change, the cursor does not blink. No reaction. I don't
understand what log should I provide.

Weston stdout and stderr are generally referred to as Weston's log.
There is also a --log command line option, but that catches only
Weston's own messages.

Post by m***@beroal.in.ua
Why should I run "weston-launch" from a virtual terminal? I would like
to run it from "gnome-terminal".

But I want to run Weston on a gfx card other than X is running on. I
have 2 gfx cards.

Ok, then you are left with the VT management issues, which I didn't
mention yet. I don't actually know what is needed to (not) do when
using a gfx card that is not used for the console. I believe this is a
use case Weston hasn't considered yet.

VT management issues might also be responsible for the "freeze" you
described.

Thanks,
pq

m***@beroal.in.ua

2016-01-07 12:36:42 UTC

Post by m***@beroal.in.ua
But I want to run Weston on a gfx card other than X is running on. I
have 2 gfx cards.

Ok, then you are left with the VT management issues, which I didn't
mention yet. I don't actually know what is needed to (not) do when
using a gfx card that is not used for the console. I believe this is a
use case Weston hasn't considered yet.
VT management issues might also be responsible for the "freeze" you
described.

I just run Xorg on "seat1" with "-sharevts" and "-novtswitch" and don't
give it much thought. I use VTs on "seat0" only.