Re: [RFC PATCH] PCI: remove access to pci_[enable|disable]_msi() for drivers

Andrew Vasquez
2005-06-07T01:09:16Z

On Mon, 06 Jun 2005, Greg KH wrote:

>
> Ok, as it seems there is a bit of confusion, here's real code that
> should help explain what I am proposing. This works on my desktop, but
> I don't think it supports MSI :)
>
> I'll go dig out an old 4-way AMD box that has MSI to see if this still
> works properly, but comments are welcome.

Thanks for posting some sample code. Some comments though:

* What if the driver writer does not want MSI enabled for their
hardware (even though there is an MSI capabilities entry)? Reasons
include: overhead involved in initiating the MSI; no support in some
versions of firmware (QLogic hardware).

* A device (notably, our 4gb PCIe fibre-channel products) can support
both MSI and MSI-X. Since the driver has no way of 'disabling' MSI,
how would it enable MSI-X?

Thanks,
Andrew