L4Linux with serial console / IRQ usage

Adam Lackorzynski adam at os.inf.tu-dresden.de
Fri Aug 11 02:02:44 CEST 2006

On Thu Aug 10, 2006 at 19:22:15 +0200, Andreas Niederl wrote:
> I have been trying to get a serial console on L4Linux with the stub 
> drivers and encountered the message 'l4ser: vkey_irq not set - input 
> disabled!'.
> Unfortunately I don't know which IRQ number is required here. I tried 
> passing some different values to L4Linux which resulted in the error 
> message 'irq_thread: RMGR denied IRQ 4: Code 0x1'.
> I'd be grateful for some hints on that.
It's 17.
> I also noticed that there are several different ways for handling IRQs 
> (omega0, rmgr, l4io, ...) which require different options for some 
> servers and L4Linux.
> Are there any documents describing the IRQ handling in L4Env and how to 
> follow one of these ways consistently?

Short summary: There's the direct way of attaching to interrupts or
using the omega0 protocol to attach to an interupt server.
l4io and omega0 both implement the omega0 interface, the 'rmgr way' is
the way to directly attach to the interrupts.
When directly attaching you need I/O port access and might have problems
with IRQ sharing which an interrupt server should fix for you, adding a
slight penalty due to the indirection.
There's a paper on omega0 at

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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