Unable to HIT IRQ4 , Serial Port Driver
 

Hi All,

I am in process of writing a serial port driver on x86 on linux.
For some reason whenever i send some data to serial port
my IRQ4 interrupt handler is not being invoked.

1) I used register_irq(..) , register my interrupt handler , which
returns success.

2) On opening /proc/interupt file i see IRQ 4 registered by my driver ,though there is not even a single hit.

3) I have set IER(Interrupt Enable Register) low four bits to 1 to enable all serial port interrupts.

Please Suggest

Thanks
Sanjay