Hi Parmenides.... On Thu, Aug 12, 2010 at 20:28, Parmenides <[email protected]> wrote: > Hi, > > For some traditional devices, such as floppy, keyboard, etc, the IRQ > is static, and their drivers know corresponding IRQs to register their > ISR. While for other devices hot plugged, such as USB devices, how > does the PIC or APIC allocate the IRQs for their controller? And how > does the deriver of a such device know the the corresponding IRQ so as > to register its ISR into the kernel?
Don't take my word for granted, this is truly a speculation: I think, let's say for USB case, IMO each USB port is already assigned a specific IRQ. But since we know that each USB port can be cascaded...for example into another 2 "port", I think here they are sharing IRQ. So, how does the kernel know which one to response or which one to send a command/data to? By looking at specific "flag". But AFAIK, still, they are sharing single interrupt line. -- regards, Mulyadi Santosa Freelance Linux trainer and consultant blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com -- To unsubscribe from this list: send an email with "unsubscribe kernelnewbies" to [email protected] Please read the FAQ at http://kernelnewbies.org/FAQ
