Re: [PATCH 1/2] msi: Invert the sense of the MSI enables.

[David Miller <davem@davemloft.net>]

From: Michael Ellerman <michael@ellerman.id.au>
Date: Fri, 25 May 2007 15:14:10 +1000

> On Thu, 2007-05-24 at 22:19 -0600, Eric W. Biederman wrote:
> > Currently we blacklist known bad msi configurations which means we
> > keep getting MSI enabled on chipsets that either do not support MSI,
> > or MSI is implemented improperly.  Since the normal IRQ routing
> > mechanism seems to works even when MSI does not, this is a bad default
> > and causes non-functioning systems for no good reason.
> > 
> > So this patch inverts the sense of the MSI bus flag to only enable
> > MSI on known good systems.  I am seeding that list with the set of
> > chipsets with an enabled hypertransport MSI mapping capability.  Which
> > is as close as I can come to an generic MSI enable.  So for actually
> > using MSI this patch is a regression, but for just having MSI enabled
> > in the kernel by default things should just work with this patch
> > applied.
> 
> I guess this is a good idea for random x86 machines. On powerpc I think
> we'll just turn it on for every bus, and let the existing per-platform
> logic decide.

I think I'll turn it on always on sparc64.