Re: [PATCH 0/3] msi abstractions and support for altix

Matthew Wilcox
2005-12-22T20:50:23Z

On Thu, Dec 22, 2005 at 02:38:24PM -0600, Mark Maule wrote:
> Because on ia64 IA64_FIRST_DEVICE_VECTOR and IA64_LAST_DEVICE_VECTOR
> (from which MSI FIRST_DEVICE_VECTOR/LAST_DEVICE_VECTOR are derived) are not
> constants. The are now global variables (see change to asm-ia64/hw_irq.h)
> to allow the platform to override them. Altix uses a reduced range of
> vectors for devices, and this change was necessary to make assign_irq_vector()
> to work on altix.

To be honest, I think this is just adding a third layer of paper over
the crack in the wall. The original code assumed x86; the ia64 port
added enough emulation to make it look like x86 and now altix fixes a
couple of assumptions. I say: bleh.

What we actually need is an interface provided by the architecture that
allocates a new irq. I have a hankering to implement MSI on PA-RISC but
haven't found the time ...