Re: Question on using MSI in PCI driver

From: Roland Dreier
Date: Tue Jun 22 2004 - 14:13:10 EST


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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/