Re: [Qemu-devel] [PATCH] upgrading emulated UART to 16550A

[Stefano Stabellini]

Jason Wessel wrote:

> I didn't spend the time to figure out what was wrong, but I thought I'd
> try your new port emulation against KGDB which is known to work with
> real hardware, as well as the existing 16450 qemu uart support.
> 
> For some reason, the initial interrupt if a character comes into the
> uart does not seem to get raised, so the kernel routine which handles
> the traffic never gets invoked.  It is possible that the that the kgdb
> kernel driver has a defect, but this does seem to work on real hardware,
> so perhaps it is a timing problem or the qemu emulation is not quite
> accurate with respect to the real hardware.
> 
> If you like, I can provide you a bzImage and the qemu invocation, such
> that you could see the problem first hand.
> 

yeah, that could help.