Re: MSI messages

Grant Grundler
2008-12-14T08:22:19Z

On Sat, Dec 13, 2008 at 01:38:24PM +0400, Manu Abraham wrote:
> Hi,
>
> I am wondering how to handle this:
>
> Does the kernel somehow handle MSI message readback from the PCI config space
> for the MSI message as described in 6.8.1 of the PCI Bus specification 2.3 or
> does a device specific driver have to read the Message Address and Data ?
>
> To put it short: i am wondering how i should read the MSI messages.

The "message" is actually mapped to an the interrupt vector by the core
generic interrupt handling code in the kernel.

A "GSI" (Generic Sys Interrupt?) is associated with each entry in
the MSI-X table. Driver then calls request_irq() to bind an interrupt
handler to each GSI. So the driver never directly sees the "message".

hth,
grant