There has been no turning back. But this is not an open source story. In fact, the embedded Linux business looks a lot like the rest of the embedded market.
Here is an example, Timesys providing subscriptions to its LinuxLink in order to help Tensilica customers get to market faster. Tensilica calls this a strategic partnership, alongside a deal with Embedded Alley Solutions to provide consulting and training.
The deals are not noteworthy in themselves, except that they point to how Linux has become the mainstream embedded technology of choice.
It's Linux' modular design, a kernel whose features designers can pick-and-choose among, which is causing this revolution in embedded systems.
As chip densities increase manufacturers outgrow the old RTOS systems, and a full-fledged operating system delivers better time to market. Microsoft is not considered viable because it lacks this key modularity, and is years from implementing it.
Microsoft is only now talking about a kernel-based design in Windows 7, which is still in the planning stages.
Outside branded areas like game machines or phones, the embedded market will have sailed away from Redmond long before it's serious about it.