[systemd-devel] Reason for logind using DRM_IOCTL_DROP_MASTER?

[Andrei Borzenkov]

I have weird case where attempt to start program on discrete card fails with

[ 1064.755339] [DEBUG][XORG] (--) using VT number 7
[ 1064.755345] [DEBUG][XORG] (II) systemd-logind: logind integration
requires -keeptty and -keeptty was not provided, disabling logind
integration
[ 1064.755351] [DEBUG][XORG] (II) xfree86: Adding drm device
(/dev/dri/card0)
[ 1064.755359] [ERROR][XORG] (EE) /dev/dri/card0: failed to set DRM
interface version 1.4: Permission denied

As far as I could trace it, it is related to logind calling
DRM_IOCTL_DROP_MASTER, as this is the only reason for ioctl to fail
with EACCESS.

This basically renders bumblebee unusable. Any reason logind needs to
call it? I have quite limited understanding of how DRM in Linux works,
so anyone could suggest what should be done here?

Thank you!