Hi [ Top-posting is a bad idea. Please don't. See http://en.wikipedia.org/wiki/Top-post ] Bhanu Kalyan Chetlapalli wrote: > The Processor gets interrupts through the PIC 8259A. Hence > during bootup we reprogram the 8259A to remap the IRQs from 0-31 range > to a more reasonable range. I'm not sure of the state of the 8259A at bootup (not sure it maps IRQs to interrupts 0-31), but anyway, you need to program it to redirect IRQs to a range of processor interrupts that are available. > For Example if we have an interrupt for an NIC, it will be shown as, > lets say, 17 in the PCI config space. But the 8259A (when we reprogram > it manually in the kernel) will remap it to some value like 49 or so. > So while registering the IRQ we use the same number 17 only to > register it. which is why ifconfig & /proc/interrupts show the number > - 17. The actual interrupt handler descriptor is placed at Index of 49 > in the IDT. You got it. Sincerly, Thomas -- Thomas Petazzoni thomas.petazzoni@xxxxxxxx -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
