[ILUG-BOM] Multiseat setup

Rajeev R. K. rajeevrk at gmail.com
Fri Aug 10 10:24:11 IST 2018


On Thu, 9 Aug 2018 at 18:51, J T Dsouza <jtd1959 at gmail.com> wrote:

> loginctl -a list-seats
> SEAT
> seat-1
> seat0
>
> 2 seats listed.
> jloginctl seat-status
> seat0
>         Sessions: *20 11 2
>          Devices:
>                   ├─/sys/devices/LNXSYSTM:00/LNXPWRBN:00/input/input5
>                   │ input:input5 "Power Button"
>
> ├─/sys/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0C0C:00/input/input4
>                   │ input:input4 "Power Button"
>                   ├─/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.0/usb1
>                   │ usb:usb1
>>
> ├─/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.0/usb1/1-5/1-5:1.0/0003:046D:C534.0001/input/input0
>                   │ │ input:input0 "Logitech USB Receiver"
>>
> ├─/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.0/usb1/1-5/1-5:1.1/0003:046D:C534.0002/input/input1
>                   │ │ input:input1 "Logitech USB Receiver"
>                   ├─/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.0/usb2
>                   │ usb:usb2
>
> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.0/graphics/fb0
>                   │ [MASTER] graphics:fb0 "amdgpudrmfb"
>
> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0
>                   │ sound:card0 "Generic"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0/input10
>                   │ │ input:input10 "HD-Audio Generic HDMI/DP,pcm=9"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0/input11
>                   │ │ input:input11 "HD-Audio Generic HDMI/DP,pcm=10"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0/input12
>                   │ │ input:input12 "HD-Audio Generic HDMI/DP,pcm=11"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0/input7
>                   │ │ input:input7 "HD-Audio Generic HDMI/DP,pcm=3"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0/input8
>                   │ │ input:input8 "HD-Audio Generic HDMI/DP,pcm=7"
>> └─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.1/sound/card0/input9
>                   │   input:input9 "HD-Audio Generic HDMI/DP,pcm=8"
>                   ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.3/usb3
>                   │ usb:usb3
>                   ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.3/usb4
>                   │ usb:usb4
>                   ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.4/usb5
>                   │ usb:usb5
>                   ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.4/usb6
>                   │ usb:usb6
>
> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.6/sound/card1
>                   │ sound:card1 "Generic_1"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.6/sound/card1/input13
>                   │ │ input:input13 "HD-Audio Generic Front Mic"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.6/sound/card1/input14
>                   │ │ input:input14 "HD-Audio Generic Rear Mic"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.6/sound/card1/input15
>                   │ │ input:input15 "HD-Audio Generic Line"
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.6/sound/card1/input16
>                   │ │ input:input16 "HD-Audio Generic Line Out"
>> └─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.6/sound/card1/input17
>                   │   input:input17 "HD-Audio Generic Front Headphone"
>                   ├─/sys/devices/platform/pcspkr/input/input6
>                   │ input:input6 "PC Speaker"
>                   ├─/sys/devices/virtual/misc/kvm
>                   │ misc:kvm
>                   └─/sys/devices/virtual/misc/rfkill
>                     misc:rfkill
>
>  loginctl seat-status seat-1
> seat-1
>          Devices:
>
>
> ├─/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.0/usb1/1-6/1-6:1.0/0003:046D:C534.0003/input/input2
>                   │ input:input2 "Logitech USB Receiver"
>
>
> ├─/sys/devices/pci0000:00/0000:00:01.2/0000:01:00.0/usb1/1-6/1-6:1.1/0003:046D:C534.0004/input/input3
>                   │ input:input3 "Logitech USB Receiver"
>
> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.0/drm/card0
>                   │ [MASTER] drm:card0
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.0/drm/card0/card0-DP-1
>                   │ │ [MASTER] drm:card0-DP-1
>> ├─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.0/drm/card0/card0-DVI-D-1
>                   │ │ [MASTER] drm:card0-DVI-D-1
>>
> └─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.0/drm/card0/card0-HDMI-A-1
>                   │   [MASTER] drm:card0-HDMI-A-1
>
> └─/sys/devices/pci0000:00/0000:00:08.1/0000:06:00.0/drm/renderD128
>                     drm:renderD128
>
> lightdm x-l.log
> Unable to retrieve master
> (EE)
> Fatal server error:
> (EE) AddScreen/ScreenInit failed for driver 0
>
> X detects the gpu, detects all 3 ports, detects both monitors with
> right modes but bombs with
>
> [    23.882] Unable to retrieve master
> [    23.882] (EE)
> Fatal server error:
> [    23.882] (EE) AddScreen/ScreenInit failed for driver 0
>

There is your problem. You only have 1 Display Device. The DRM subdevices
arent independent devices, but rather all paired with the a single
framebuffer device. assigning the DRM devices and the framebuffer device to
separate seats does not magically make them 2 separate seats. Basically the
error above is because the DRM(Rendering) portion of the drivers arent able
to find a place to render into, A.k.A a framebuffer. The basic requirement
for this style of multiseat is a separate framebuffer per seat, which you
only get with separate graphics cards, not a single card that just happens
to have multiple outputs. In such a scenario, we would have to go with a
xnest type solution, which is the direction my experiments are moving in.

Thanks and Regards

R. K. Rajeev
Ph : +91-9323802020


>
> On Thu, Aug 9, 2018 at 12:28 PM, J T Dsouza <jtd1959 at gmail.com> wrote:
> > On Wed, Aug 8, 2018 at 11:43 AM, Rajeev R. K. <rajeevrk at gmail.com>
> wrote:
> >> On Tue, 7 Aug 2018 at 17:28, J T Dsouza <jtd1959 at gmail.com> wrote:
> >
> >>> Trying it out on a gigabyte AB350+ Ryzen 5 2600gpu. Which has 3
> >>> outputs. With loginctl I can split the devices between 2  seats quite
> >>> easily.
> >>>
> >>>
> >> There are you using the On-Board Display ports as seat 0, and the addon
> GPU
> >> ports as seat1? Or do you have multiple on-board ports with a single
> >> display controller serviing multiple seats?
> >
> > Single on board gpu (AMD Vega11) with multiple display controllers.
> > There are 3 - HDMI, D-sub (VGA) and DVI-D
> > I am trying to use HDMI and VGA.
> > So far havent been able to start 2 independent tty or x session, one
> > each on each display. It is always one login. Copy whne it is a tty
> > and xinerama when X. Option Xinerama 0 has no effect.
> > lightdm starts 2 X sessions one for seat0 and one for seat-1 but gets
> > no response from the one being started on VGA, and shuts that down.
> >
> >> Could you share your 'loginctl
> >> seat-status' output?
> >
> > Will post later alongwith xorg.0.log xorg.1.log.
> --
> https://mm.ilug-bom.org.in/mailman/listinfo/linuxers


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