Hi All

We have a NetBSD system, in which two devices share an interrut line
(IRQ12). The one device (a serial chip), takes approximately 1us to check if
the interrupt was caused by itself, and the other device (an i2c device),
takes approximately 30ms to check if it caused the interrupt. It is not
ideal that everytime the serial chip interrupts, 30ms is spent seeing if it
was the i2c device! We would thus like to first check the serial chip, and
only pass the interrupt on to the i2c device if it was not caused by the
serial device. It is also not a problem if both devices interrupt
simultaneously, but only the cirrus services the interrupt, as this will
cause a re-interrupt for the i2c device in hardware.

Does anybody have any suggestions as to how we can handle this problem, as
NetBSD seems to call both interrupt service routines?

Thanks
Bruce Martin.