[systemd-devel] Reason for logind using DRM_IOCTL_DROP_MASTER?

[David Herrmann]

Hi

On Fri, Sep 18, 2015 at 2:09 PM, Andrei Borzenkov <arvidjaar at gmail.com> wrote:
> 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

This is a log of Xorg, not systemd. It sounds like you run it without
"-keeptty", and also as non-root. Most likely a mis-configuration, but
the Xorg community is the place to get help. This sounds very
unrelated to systemd.

> 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.

Are you sure? How did you verify that this is the culprit?

> 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?

Please be a lot for verbose about your setup and what you're trying to
do. Otherwise, it's very hard to help you.

Thanks
David