Kernel problem with multiseat on one card - more than 1 user simultaneously on 1 video card

[Ilia Mirkin]

On Sat, Dec 28, 2024 at 7:39 AM Gert Vanhaerents <
gert.vanhaerents at hotmail.com> wrote:

> In the meantime I have contacted everyone who could have something to do
> with it:
> Kernel groups
> System D
> Nvidia
> And gues:  Everyone says it's not their fault.
>
> But we don't give up. Linux is such a beautiful and solid system. Why
> would it work with Windows and not Linux?u
>
> Our analysis has now discovered that the problem does indeed come from
> the kernel. The kernel does not allow several users to access a graphics
> card at the same time. Indeed, to use it, several users need access to
> the graphics card at the same time.
>
> Can this simultaneous access be allowed by the kernel after all?
> Or can the kernel be adjusted so that this would be possible?
>
> In the meantime I am also working with a multiseat company to search
> together for a solution for multiseat under Linux. This company is
> working on creating an easy and user-friendly program to work via a
> multiseat with Linux, and they have already a high-selling multiseat
> program for Windows. The intention would be to create a program that
> works like some multiseat programs in Windows: install, drag mice and
> keyboards to the right screen, restart and it works as multiseat.
> But such a program is only interesting if it can work for different
> users on 1 video card. For example, for a multiseat of 6 users you need
> 3 video cards with 2 outputs each.
> For now the programmers has a good béta program, but with the
> restriction only one workstation on one video card, but then it's not
> interesting at all.


You don't mention which GPU you have. Pre-Kepler GPUs can only scan out 2
outputs at a time, so even if you have 3+ connectors on the board, you can
still only have 2 of them active at a time. This is a hardware restriction.
Kepler+ enables 4.

If you check "lspci -nn -d 10de:" it should give you all the NVIDIA
hardware in your machine.

Cheers,

  -ilia

P.S. Looks like I provided this very same advice to you without response on
Jan 16, 2024. So it's an annual thing?
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