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

[Eric W. Biederman]

Michael Ellerman <michael@xxxxxxxxxxxxxx> writes:

> 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.

Yep.  That is pretty much what I expected.

Since you already have to detect how to implement the MSI methods
you need a separate white list anyway.

Just a side note.  This only needs to be enabled for pci root
busses.

Eric
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