Workaround race conition in uDMX driver
Workaround race conition in uDMX driver

Avoid deadlock if device is closed before thread has started

Signed-off-by: Paul Brook <a027184a55211cd23e3f3094f1fdc728df5e0500@nowt.org>

sbenejam/qlcplus,mcallegari/qlcplus,peternewman/qlcplus,sbenejam/qlcplus,joepadmiraal/qlcplus,sbenejam/qlcplus,joepadmiraal/qlcplus,bjlupo/rcva_qlcplus,sbenejam/qlcplus,peternewman/qlcplus,plugz/qlcplus,hveld/qlcplus,mcallegari/qlcplus,nedmech/qlcplus,mcallegari/qlcplus,plugz/qlcplus,joepadmiraal/qlcplus,kripton/qlcplus,nedmech/qlcplus,joepadmiraal/qlcplus,kripton/qlcplus,bjlupo/rcva_qlcplus,plugz/qlcplus,joepadmiraal/qlcplus,nedmech/qlcplus,nedmech/qlcplus,kripton/qlcplus,kripton/qlcplus,bjlupo/rcva_qlcplus,joepadmiraal/qlcplus,bjlupo/rcva_qlcplus,hveld/qlcplus,nedmech/qlcplus,nedmech/qlcplus,kripton/qlcplus,plugz/qlcplus,mcallegari/qlcplus,mcallegari/qlcplus,sbenejam/qlcplus,mcallegari/qlcplus,hveld/qlcplus,peternewman/qlcplus,kripton/qlcplus,hveld/qlcplus,peternewman/qlcplus,kripton/qlcplus,sbenejam/qlcplus,sbenejam/qlcplus,hveld/qlcplus,peternewman/qlcplus,hveld/qlcplus,bjlupo/rcva_qlcplus,mcallegari/qlcplus,plugz/qlcplus,plugz/qlcplus,peternewman/qlcplus,plugz/qlcplus,bjlupo/rcva_qlcplus