Jan Kiszka wrote:
> The 8250 UART emulation currently raises a TX-done IRQ immediately when 
> the guest writes out some character. This is problematic for guests like 
> Linux which may flush its output buffer in a loop from IRQ context, 
> because they may then enter a tight loop with IRQs disabled. In fact, 
> Linux breaks out of this loop after some iterations and issue the 
> well-known [1] "too much work for irq..." warning. And in case the 
> console output is on the very same serial port, the console output is 
> utterly corrupted.
> 
> Patch below addresses the issue by delaying the TX-done IRQ more 
> realistically, ie. according to the currently set baudrate.
> 
> Jan
> 
> [1] http://lkml.org/lkml/2008/1/12/135
> 
> Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
> 

Sorry, my TB obviously "gained" some regression, now wrecking inline 
patches even in do-not-wrap mode. That used to work for ages. Dreck.

Clean patch attached.

Jan