Patch for using dual serial/internal consoles?

[frenzy at frenzy.org]

I remember hearing some time ago about someone who had written a kernel
patch so you could use both the serial and internal console.
Unfortunately, I can't seem to find the patch anywhere.

I have a few servers setup using a console server for remote serial
console access, and would also like the capability to have a kvm setup at
the same time that the console has been directed to the serial device.

Could anyone point me in the right direction for any work done on this 
issue? I am especially interested in the 5.x kernel. 

Thanks,

Randy