> Hmm... > I find in section 6.1: > > In addition to PCI INTx compatible interrupt emulation, PCI Express > > requires support of MSI or MSI-X or both.
> Which suggests that INTx support is required. Unfortunately, this can be equally well read to suggest that MSI/MSI-X is not required, but that MSI/MSI-x is required in addition if you choose to support PCI INTx. Section 6.1 is ambiguous and you have to look elsewhere to figure out if PCI INTx is required or not. I think the most natural reading of this is that if you choose to support PCI INTx compatible interrupt emulation, PCI Express requires support of MSI or MSI-X or both in addition. However, other sections are not ambiguous: "For legacy compatibility, PCI Express provides a PCI INTx emulation mechanism to signal interrupts to the system interrupt controller (typically part of the Root Complex). This mechanism is compatible with existing PCI software, and provides the same level and type service as corresponding PCI interrupt signaling mechanism and is independent of system interrupt controller specifics. This legacy compatibility mechanism allows boot device support without requiring complex BIOS-level interrupt configuration/control service stacks. It virtualizes PCI physical interrupt signals by using an in-band signaling mechanism." This seems to make it pretty clear that if a device requires MSI/MSI-X, it is broken. Devices are supposed to work even with PCI drivers that are not smart enough to support MSI/MSI-X. DS - 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/
