From: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Date: Mon, 14 Jul 2008 10:17:39 +1000 > On Sun, 2008-07-13 at 16:29 -0700, Eric W. Biederman wrote: > > Ben. Multi-MSI is a crap hardware design. Why do you think we have > > MSI-X? > > I know and I agree. Which is why I'd rather keep the SW crap totally > local to the MSI support code and not add new concepts to the generic > IRQ API such as sub-channels, for which it's really not ready for imho. > > They -are- separate IRQs, just badly implemented. Besides, a large part > of the problem is purely due to the typical x86 implementation of them, > since for example, on most PowerPC's (and possibly other archs), they > tend to land in the PIC as normal sources, and as such benefit from all > the "features" of such interrupts like HW masking, affinity control, > etc... at the PIC level. This is how it works on sparc64 too. The x86 system designers decided to implement multi-MSI in an inconvenient way, it is not a "crap hardware design", merely some (unfortunately common) implementations of it happen to be. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
