Sunday, 3 April 2016

VT calls failing on /dev/console

Hi all,

I've noticed in Xenial that VT ioctls that LightDM is using (VT_GETSTATE, VT_ACTIVATE, VT_WAITACTIVE) on /dev/console now seem to be failing (errno 5 - Input/output error). If I switch to /dev/tty0 they seem to work (this is what GDM and logind are using).

Two questions:
- Does anyone know what has changed that means these no longer work?
- What is the correct way to do these VT calls? Every time i try and work this out there seems to be no documentation anywhere and reading the kernel leaves me more confused.