Re: [PATCH 2/4 v2] PCI: support ARI capability

[Matthew Wilcox <matthew@wil.cx>]

On Wed, Sep 10, 2008 at 03:48:04PM +0800, Zhao, Yu wrote:
> >I agree with this improvement to the help text.  But a further question
> >is whether ARI even merits its own user-visible config option.  Is it
> >worth having yet another choice for users?  When would someone want ARI
> >but not SR-IOV?
> 
> ARI is an independent PCI Express extended capability. Multi-function devices supporting this capability may use it to track dependency between different functions and assign function group numbers to these functions.
> 
> Another reason to keep this separated with SR-IOV is that after ARI is enabled, PCI Express Endpoint may have non-zero slot number (device number), which is different from traditional PCI Express Endpoint.

Let me ask the question slightly differently: Why would someone want to
turn the capability off?  Is it just to save a few hundred bytes in the
kernel image, or is there some hardware that won't work?  Or some other
reason I haven't thought of?

-- 
Matthew Wilcox				Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours.  We can't possibly take such
a retrograde step."