[systemd-devel] [PATCH 10/10] logind: implement generic multi-session

[David Herrmann]

Hi

On Sun, Aug 25, 2013 at 5:17 PM, Tom Gundersen <teg at jklm.no> wrote:
> Hi David,
>
> On Sun, Aug 25, 2013 at 8:46 PM, David Herrmann <dh.herrmann at gmail.com> wrote:
>> One important note is that delayed session-switching is meant for
>> backwards compatibility. New compositors or other sessions should really
>> try to deal correctly with forced session switches! They only need to
>> handle EACCES/EPERM from syscalls and treat them as "PauseDevice" signal.
>>
>> Following logind patches will add a timeout to session-switches which
>> forces the switch if the active session does not react in a timely
>> fashion. Moreover, explicit ForceActivate() calls might also be supported.
>> Hence, sessions must not crash if their devices get paused.

[...]
> Do you have reason to believe that handling EACCESS would be
> significantly harder than just porting to the PauseDevice interface?
[...]

Yes.

For the XServer device handling is done in drivers. There are many of
xf86-video-* drivers and I have no intention to fix all of them. Note
that device-enumeration (udev etc) is done in the xserver core. This
could be fixed more easily.

But as said in the introduction-text, this is *only* for
compatibility. And the longer I think about it, I get more and more
convinced to drop it all-together. It's handy to test it and play
around with it, but maybe the final revision would be better off
without it. If anyone wants to run an xserver with it, they ought to
use a driver that can deal with asynchronous session-switches.

Cheers
David