This error only occurs when xserver or another program is the drm master at the time we start mir. As far as I know we dont get it at startup anymore because lightdm gets sure that plymouth -which is a drm master- has stopped when xmir starts (which means that xmir can "safely" become the drm master).
We only get the error in cases like this:
xserver is running along with xmir
then for some reason we stop and start xmir
before mir starts and unity desktop shows up, we switch to the xserver graphics tty (so xserver becomes the drm master)
we switch back to the xmir and we get the open drm device error because xmir failed to become the drm master..
I don't know what we could do in this case except of printing a more relevant error message. There can be one master only and if this master is xserver we wouldn't like to crash it for mir to become the master in his place. So, I don't know how to fix this and if we really need to fix it. (If xserver runs rootless at some point we won't have that problem anymore).
This error only occurs when xserver or another program is the drm master at the time we start mir. As far as I know we dont get it at startup anymore because lightdm gets sure that plymouth -which is a drm master- has stopped when xmir starts (which means that xmir can "safely" become the drm master).
We only get the error in cases like this:
xserver is running along with xmir
then for some reason we stop and start xmir
before mir starts and unity desktop shows up, we switch to the xserver graphics tty (so xserver becomes the drm master)
we switch back to the xmir and we get the open drm device error because xmir failed to become the drm master..
I don't know what we could do in this case except of printing a more relevant error message. There can be one master only and if this master is xserver we wouldn't like to crash it for mir to become the master in his place. So, I don't know how to fix this and if we really need to fix it. (If xserver runs rootless at some point we won't have that problem anymore).
Any ideas?
PS: I think it's not a critical bug anymore...