Re: Question on using MSI in PCI driver

[Roland Dreier <roland@topspin.com>]

    Tom> The PCI 3.0 specification has implementation notes that MMIO
    Tom> address space for a device's MSI-X structure should be
    Tom> isolated so that the software system can set different page
    Tom> for controlling accesses to the MSI-X structure. The
    Tom> implementation of MSI patch requires the PCI subsystem, not a
    Tom> device driver, to maintain full control of the MSI-X
    Tom> table/MSI-X PBA and MMIO address space of the MSI-X
    Tom> table/MSI-X PBA. A device driver is prohibited from
    Tom> requesting the MMIO address space of the MSI-X table/MSI-X
    Tom> PBA. Otherwise, the PCI subsystem will fail enabling MSI-X on
    Tom> its hardware device when it calls the function
    Tom> pci_enable_msi().

Thanks.  I guess for the time being I will have to split up my request
region calls.

Do you think the msi subsystem should use a different name for the
MSI-X memory region ("MSI-X iomap Failure" seems very strange to me).

 - Roland