[mythtv-users] OT? /proc/pci
Jason Kraftcheck
jkraftch at facstaff.wisc.edu
Mon Jul 12 16:00:23 EDT 2004
Joel Anderson wrote:
> Marc-David Meijer wrote:
>
> As I understand it, PCI devices don't depend on IRQs anyway. They use
> interrupt "channels", and IRQs are just kept around to keep legacy stuff
> happy. You will often see many devices appear to "share" the same IRQ,
> but it is not really true since IRQ's can't really _be_ shared.
>
> Someone please comment if I haven't explained this correctly. It's a
> simplification, but it basically means that IRQ issues shouldn't come
> into play unless you have some legacy hardware in the system also.
I'm no expert either, but I think they are actually "shared". The
interrupt handler must poll each device by invoking the interrupt
handler in the driver for each device sharing the interrupt. Thus
there's a slight performance loss when sharing interrupts, and also the
possibility for buggy drivers to interfere with each other.
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