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#1 2014-08-21 00:57:09

bnb2235
Member
Registered: 2011-02-13
Posts: 115

[SOLVED] Multiseat with GDM3 and systemd

Hello,
I am looking for advice on Multiseat. I have read so much information about Multiseat and different ways to do it. I read on userful.com about their CentOS and their HP t200 network based zero clients. A quite interesting page is here. The documentation at freedesktop.org suggests that Multiseat is nearly automatic now. I found a post of someone asking the same basic question as me, but the answer was not very complete. So I have to ask, is Multiseat working now on an up to date system? l0vot surely suggested Multiseat is not so good in this post.

My goal is to move to two seats of Multiseat, but I am unsure of how it is working now. Does anyone have Multiseat working with Gnome3? I have a Dell 790 SFF, quad core i5 2400, with 8GB RAM. I have two free PCI-e slots (one 4x, one 16x). Can I add two fanless video cards and get Multiseat to work? Which card would work better ATI, or nVidia? The wiki seems out of date because systemd seems to have changed what is written there.

For me, I am not so concerned about sound even. A "simple" setup... If one user can get the sound and the other user gets no sound, that is OK with me (at least for now)

Can anyone shed any current information?

Thank you

Last edited by bnb2235 (2014-09-19 23:36:28)

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#2 2014-08-23 23:56:13

bnb2235
Member
Registered: 2011-02-13
Posts: 115

Re: [SOLVED] Multiseat with GDM3 and systemd

I did find some more interesting information written about Fedora, but I would think it applies to Arch because of systemd...
Multiseat in Fedora 19
Setting up a multiseat system
lesbg-multiseat-1.2-1.fc19
reddit.com

And a youtube video with Fedora 20 and a pluggable device:
youtube video

Looks like I may just have to buy some hardware and try it...

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#3 2014-08-30 01:57:24

bnb2235
Member
Registered: 2011-02-13
Posts: 115

Re: [SOLVED] Multiseat with GDM3 and systemd

I have it working...

I purchased two ATI 6350 cards. I do no gaming or intense graphics, so these should be just fine. My motherboard supports up to 25W in the PCI-e 4x slot and up to 35W in the PCI-e 16x slot. The 6350 card is 20W max. I do believe this setup would have been possible with only one card and the built in Intel card, but two of the same cards has to be better ;-) For reference, in this Dell 790, a card in the 16x slot will disable the Intel graphics, but a card in the 4x slot will work simultaneously with the Intel graphics. These 6350 cards (not all 6350 cards are the same) have a DMS-59 connector. This requires a DVI "splitter" cable to connect to DVI. I quote "splitter" because it is not a traditional splitter cable, but the method used to get two heads out of a low profile card.

I found another page (actually MultiSeat pages are not so hard to find now that I know the right keywords)
http://code.lexarcana.com/posts/simple- … ra-17.html

with the command

$ loginctl seat-status seat0

I am able to find all the information I need.
I need card 1 ([MASTER] graphics:fb1 "radeondrmfb"), so I need to attach two lines to seat1 for the video card

# loginctl attach seat1 /sys/devices/pci0000:00/0000:00:1c.4/0000:04:00.0/drm/card1
# loginctl attach seat1 /sys/devices/pci0000:00/0000:00:1c.4/0000:04:00.0/graphics/fb1

Now I also want to control which devices (usb drives, keyboard, mouse, etc...) go to seat1 (by default, all unassigned devices go to seat0) so the easiest thing is to bind a USB hub to seat1. So I connect the mouse and keyboard to the hub (for easier identification purposes in the loginctl seat-status seat0 command. I look up the tree and find the correct line. So for me, I attached the hub.

# loginctl attach seat1 /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.7

Now all devices in that hub will be bound to seat1.

So now, not only do I have MultiSeat, I actually have MultiMonitor MultiSeat. (two workstations, each with dual displays)

GDM is enabled, and after a reboot, I have two independent logon screens.

Now I need a little time to see how I like it ;-)

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#4 2014-09-19 23:35:53

bnb2235
Member
Registered: 2011-02-13
Posts: 115

Re: [SOLVED] Multiseat with GDM3 and systemd

Hello,
I thought I would do an update to this post and also mark it solved. I now have sound on both seats. The solution for this was also quite simple. A usb sound card... I bought this one (although the price was $6.39 when I bought it) There are many cheap usb sound cards, but I liked the models which have a wire on them so as not to block the other usb ports. I upgraded the monitor which is on seat1. I changed to a HP LP2065 (same as the monitor on seat0). This provides a four port, powered usb hub. That is ideal for this situation. It did seem that the powered hub was essential to make the sound card work. In any case, the usb sound card was the easy solution to add sound on the second seat. Since it is connected to the hub which is tied seat1, no additional provisioning was necessary either.

Another quick story. This computer used to be my server and ran all of the time. I used to charge phones from usb wires which were connected to the computer. Now my needs have changed (hence the multi seat configuration), so I am suspending the computer. This added a few complications.
1. The wireless logitech keyboard would not wake the computer.
2. Now charging devices was not so functional because when the computer suspends, no more power is available at the usb ports (Dell 790 only has USB 2.0, not 3.0)

At first, I added a rule to add wakeup for the keyboard. Reference this. However, this also made a problem for me. Since the mouse and keyboard are on the same receiver, the mouse wakes up the computer too... This is not what I wanted. I put the keyboard on one receiver, and the mouse on another receiver. Actually, I have four receivers in total, because both seats have the same keyboards and mice (Logitech K360 and M510). I wrote a rule which is working well. I am only guessing, but it seems that whatever device is assigned to a unifying receiver, it adds a specific PID. So at least for these K310 keyboards, that PID is 4004. So writing the rule to add wake from usb was easy. The rule is not very explicit.

/etc/udev/rules.d/90-keyboard-wakeup.rules

SUBSYSTEM=="input", ATTR{name}=="Logitech Unifying Device. Wireless PID:4004" RUN+="/bin/sh -c 'echo enabled > /sys$env{DEVPATH}/../../../../../power/wakeup'"

Now the keyboards will wake the computer, but not the mice. This is what I want. It is a waste to use a receiver for each device since each receiver can handle six devices, but I know no other way to wake from keyboard, but not the mouse too.

The solution for point 2 was a multi wire usb charge wire. I connected this wire to a AC wall adapter. This provides charging for multiple devices.

Another interesting thing... I have the standard usb powered HP speaker bar on both of these HP monitors. For as long as I have had a usb powered speaker bar, they have always made a buzzing noise when the volume is high (and the computer is not emitting sound). I got the idea to connect the usb of the speaker (the "power" cord) to the AC wall adapter. The speaker buzz was significantly better. So in the end, I connected a usb hub to the AC adapter. Now the phone charge wire, and both speaker bars are powered by the AC adpater via the usb hub. That is working surprisingly well....

I also want to add that unlike the problem suggested in the wiki regarding multi media keyboards, I have had no problems with the keyboards. All of the special keys like volume, calculator, mail, etc... are all working fine.

Also, on seat0, I still have the ctrl + alt + Fn functionality to get to a new virtual terminal. This functionality does not exist on seat1.

Other interesting points. Fast user switching also seems to work (maybe beneficial if you have more users than seats). Any user can log into any seat, and all is normal.

I still have the resume after suspend issue, but this is minor, and the easy workaround is to wiggle the mouse of the other seat after a resume from suspend.

In summary. I am quite amazed at how well multi seat Linux is working and how easy it was to setup. A big Thank You to all of the Linux and software developers.

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