[PATCH 2/3 v2] powerpc/mpic: Use the MPIC_LARGE_VECTORS flag for FSL MPIC.

[Sethi Varun-B16395]

> -----Original Message-----
> From: Kumar Gala [mailto:galak at kernel.crashing.org]
> Sent: Monday, July 09, 2012 7:58 PM
> To: Sethi Varun-B16395
> Cc: linuxppc-dev at lists.ozlabs.org
> Subject: Re: [PATCH 2/3 v2] powerpc/mpic: Use the MPIC_LARGE_VECTORS flag
> for FSL MPIC.
> 
> 
> On Jul 9, 2012, at 3:46 AM, Varun Sethi wrote:
> 
> > We should use the MPIC_LARG_VECTORS flag while intializing the MPIC.
> > This prevents us from eating in to hardware vector number space (MSIs)
> > while setting up internal sources.
> >
> > Signed-off-by: Varun Sethi <Varun.Sethi at freescale.com>
> > ---
> > arch/powerpc/sysdev/mpic.c |    2 +-
> > 1 files changed, 1 insertions(+), 1 deletions(-)
> 
> Can you remind me the issue here w/running into the MSIs?
Vector numbers for internal interrupt sources like timers/ipis are
taken from the hardware vector number space. Currently we specify 
number of interrupt sources as 256 and extract 12 vectors from here
for internal interrupt sources. In process we end up eating vector numbers
meant for MSIs. With this patch we are basically expanding our vector
number space.

-Varun