[RFC PATCH 1/7] serial: Emulate break using control characters

[One Thousand Gnomes]

> > To be clear I included the patch in this series only because:
> > 
> > 1. I couldn't figure out any way to send a serial break to the ARM
> >    Foundation Model making it impossible for me to provoke SysRq actions
> >    from interrupt context,
> 
> Agreed, there's no direct way to do it (annoyingly).
> 
> Arguably that's a deficiency in the model, though that's not much help to
> you right now.

If it isn't affecting real hardware and it's just for a flawed model then
hack a check for a suitable symbol into the specific patches for
the model and its serial driver and claim it was a break - don't dump it
into the mainstream.

There are some "conventional" escapes platforms have used (ctrl and
symbols for example such as ctrl-^) which are less likely to cause
conflicts than sequences. Nevetheless its not something you want anywhere
mainstream if you can avoid it because those symbols could be sent over a
remote management modem or similar.

They may be better if it does need to end up in the core kernel.

Alan