IRQ problem in multifunction PCMCIA card

[Komuro]

Hello,

> I have a true multifunction PCMCIA card with UART function as function 0
> and USB function as function 1.
> The USB is OHCI compliant and UART is 16950 standard.
> 
> We are facing a problem of irq handling when both of the functions are
> running simultaneously.

Megahertz EM1144, EM3288 and EM3336 have same problem.
(See BUGS file of pcmcia-cs package)

ISA interrupts are LEVEL-triggered.
So if interrupt line become HIGH
and not become LOW by some reason, 
new interrupts are all ignored.

To avoid this, I think polling the interrupts is 
a solution.

Actually, serial_cs driver do the polling,
but I think the frequency of polling to be more high.

Best Regards
Komuro