Re: [PATCH] PCI MSI Kconfig consolidation

[Bjorn Helgaas]

On Tuesday 13 April 2004 1:16 pm, Nguyen, Tom L wrote:
> On Tuesday, April 13, Bjorn Helgaas wrote:
> 
> > This consolidates the PCI MSI configuration into drivers/pci/Kconfig,
> > removing it from the i386, x86_64, and ia64 Kconfig.
> >
> > It also changes the default for ia64 from "y" to "n".  The default on
> > i386 is "n" already, and I'm not sure why ia64 should be different.
> 
> It looks good; however, it may create a confusion on ia64 because ia64 
> is already vector-based indexing. 

No.  This is one reason why I think the MSI configuration symbol
should be CONFIG_PCI_MSI, not CONFIG_PCI_USE_VECTOR.

The fact that external interrupts in the ia64 architecture include a
number, and that we happen to call that number a "vector", has
nothing to do with PCI MSI.

In fact, I think there's a whole lot more architecture-specific
knowledge that has leaked across into drivers/pci/msi.[ch].  For
example, the MSI capability basically defines just a message address
register and a message data register.  It does not define anything
about the interpretation of either address or data.  So all the stuff
in struct msg_data and struct msg_address (vector, delivery_mode,
level, trigger, dest_id, dest_mode, redirection_hint) looks to me
like Intel-specific knowledge that should be encapsulated in the
arch code.
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