Re: [PATCH v3 -tip 5/5] AHCI: Support multiple MSIs

[Jeff Garzik]

On 10/02/2012 12:21 AM, Bjorn Helgaas wrote:
> On Mon, Oct 1, 2012 at 9:04 PM, Jeff Garzik <jgarzik@xxxxxxxxx> wrote:
> > On 10/01/2012 04:13 AM, Alexander Gordeev wrote:
> > > Take advantage of multiple MSIs implementation on x86 - on systems with
> > > IRQ remapping AHCI ports not only get assigned separate MSI vectors -
> > > but also separate IRQs. As result, interrupts generated by different
> > > ports could be serviced on different CPUs rather than on a single one.
> > >
> > > In cases when number of allocated MSIs is less than requested the Sharing
> > > Last MSI mode does not get used, no matter implemented in hardware or not.
> > > Instead, the driver assumes the advantage of multiple MSIs is negated and
> > > falls back to the single MSI mode as if MRSM bit was set (some Intel chips
> > > implement this strategy anyway - MRSM bit gets set even if the number of
> > > allocated MSIs exceeds the number of implemented ports).
> > >
> > > Signed-off-by: Alexander Gordeev <agordeev@xxxxxxxxxx>
> > > ---
> > >    drivers/ata/ahci.c    |   91 ++++++++++++++++++++++++++++++++++++--
> > >    drivers/ata/ahci.h    |    6 +++
> > >    drivers/ata/libahci.c |  118
> > > ++++++++++++++++++++++++++++++++++++++++++++++---
> > >    3 files changed, 205 insertions(+), 10 deletions(-)
> >
> >
> > Acked-by: Jeff Garzik <jgarzik@xxxxxxxxxx>
> >
> > Normally, this amount of changes would -really- need to go through the
> > libata tree.  However, given the amount of dependencies, it either needs a
> > merge tree or to go through the PCI tree...?
> >
> > Any maintainer comments on disposition?
>
> For what it's worth, the bulk of this change is outside PCI, so it
> doesn't seem to me like it should go through the PCI tree.  I think I
> did ack the part that touched PCI, and there's not much activity in
> the PCI MSI area right now, so I'm fine with it going through libata
> or whatever people think makes sense.

That works for me, too.  I'm ready to queue it, if libata tree is fine 
with people.

	Jeff




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