parport - interrupt sharing possible?
Hi,
Does anyone know if the generic parport interrupt handler is okay (or not) for sharing interrupts? The reason I ask is that I have a PCI parallel card with two ports on it. Without a IRQ sharing capability, it is not possible for both of them to operate in interrupt-driven mode. I tested a quick hack to enable IRQ sharing:
http://home.icequake.net/~nemesis/parport.diff
and it seems to work okay with both ports in use. I'm hoping someone more knowledgeable on the parallel port subject (Tim Waugh?) can shed some light on whether this is acceptable or not. The interrupt handler eventually ends up in parport_ieee1284_interrupt which really doesn't do much besides wake up sleepers.
Thanks!
PS: Heh, the power just went out and back on as I wrote this. Giving thanks for having multiple UPS units around!
Signature · 1 line
Ryan Underwood, <[email protected]>
Quoted 16 lines · Ryan Underwood
Hi,
Does anyone know if the generic parport interrupt handler is okay (or not) for sharing interrupts? The reason I ask is that I have a PCI parallel card with two ports on it. Without a IRQ sharing capability, it is not possible for both of them to operate in interrupt-driven mode. I tested a quick hack to enable IRQ sharing:
http://home.icequake.net/~nemesis/parport.diffand it seems to work okay with both ports in use. I'm hoping someone more knowledgeable on the parallel port subject (Tim Waugh?) can shed some light on whether this is acceptable or not. The interrupt handler eventually ends up in
parport_ieee1284_interruptwhich really doesn't do much besides wake up sleepers.
Quoted 4 lines
Thanks!
PS: Heh, the power just went out and back on as I wrote this. Giving thanks for having multiple UPS units around!
Hi Ryan,
Quoting Tim Waugh:
Quoted 3 lines
2) Allows PCI parallel port to share an IRQ if possible. In limited testing this seems to be ok, but maybe the interrupt handler was not written for sharing. Someone else will need to ok this.
This seems dangerous to me. There are some issues with IRQs in parport, although I think they are known and there is a fix around:
http://lists.infradead.org/pipermail/linux-parport/2004-March/000048.html
Incidentally, I have asked if there is anyone with more time than me who would like to maintain the paride/parport bits, but no-one has stepped forward. I see that Al Viro has fixed a lot of problems while I've been busy with other things.