David Miller wrote: > From: "H. Peter Anvin" <[EMAIL PROTECTED]> > Date: Sat, 26 May 2007 19:34:26 -0700 > >> There are systems which only get a single bit indication that an MSI has >> happened. >> >> Presumably we need something like IRQF_MSI which can be set as >> appropriate depending on the architecture? > > Although I don't want to make the IRQ handling subsystems any more > complicated than they already are, one idea I floated around is that > we could seperate CPU irq numbers (the things we pass around today) > and MSI vector numbers. > > But I immediately understand how that is unnecessary to some extent, > any platform which needs to deal with that kind of distinction can use > virtual IRQ numbers like sparc64 and powerpc do. > > Sparc64 PCI-E controllers, for example, allow you to group several > MSIs into a 'group', and the interrupt source is for the group rather > than the individual MSIs. When the MSI group interrupt arrives, you > get a descriptor in a per-MSI-group ring buffer that describes the MSI > that arrived. > > This descriptor in fact passes on a ton of interesting information, > see arch/sparc64/kernel/pci_sun4v.c:pci_sun4v_msiq_entry. > > It gives you the type, the system TSC value at the time of interrupt > arrival (so you could do incredibly cool profiling with this), > the PCI bus/device/fn that generated the MSI vector, the MSI address > that was signalled, the MSI data field, and full information for PCI-E > MSG packets including bus/dev/fn of target, the message routing code, > and the message code. > > But we use none of these facilities currently because it's either > impossible or too cumbersome to be useful at the moment. >
I think it is better to use IRQF_MSI as HPA suggested, since IRQF_SHARED is a bit confusing thing altogether since MSI doesn't share interrupts. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
