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From: YongHyeon PYUN <pyunyh@gmail.com>
Date: Wed, 18 Jan 2012 14:14:15 -0800
To: John Baldwin <jhb@freebsd.org>
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Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org,
	src-committers@freebsd.org, Pyun YongHyeon <yongari@freebsd.org>
Subject: Re: svn commit: r230286 - head/sys/dev/bge
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On Wed, Jan 18, 2012 at 09:53:51AM -0500, John Baldwin wrote:
> On Tuesday, January 17, 2012 5:15:33 pm Pyun YongHyeon wrote:
> > Author: yongari
> > Date: Tue Jan 17 22:15:33 2012
> > New Revision: 230286
> > URL: http://svn.freebsd.org/changeset/base/230286
> > 
> > Log:
> >   Introduce a tunable that disables use of MSI.
> >   Non-zero value will use INTx.
> 
> Hmm, do you think it is best to do this on a per-device level vs a per-driver 
> level (e.g. a 'hw.<driver>.msi' tunable ala mfi(4))?  Also, I think it is 

I thought that too. But what if other bge(4) controller on the box
works with MSI? I admit it would be rare case but making it
per-device-level wouldn't hurt.

> better to have a flag whose value more closely matches enable/disable (so 1 
> for enable, etc.) and default it to on, than to have a 'disable' tunable.
> 

The decision was made to make it easy to support MSIX in future.
If controller supports both MSIX and MSI, the suggested scheme may
confuse users but I don't have strong opinion on that so will
follow your suggestion.

Thank you.