Date: Sat, 29 Sep 2001 18:03:07 -0700 From: Peter Wemm <peter@wemm.org> To: Ian Dowse <iedowse@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/i386/conf NOTES src/sys/conf options src/sys/dev/ed if_ed.c if_ed_pccard.c if_edvar.h Message-ID: <20010930010307.88FB7380A@overcee.netplex.com.au> In-Reply-To: <20010929235909.E6894380A@overcee.netplex.com.au>
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Peter Wemm wrote:
> Ian Dowse wrote:
> > iedowse 2001/09/29 15:32:03 PDT
> >
> > Modified files:
> > sys/i386/conf NOTES
> > sys/conf options
> > sys/dev/ed if_ed.c if_ed_pccard.c if_edvar.h
> > Log:
> > Add an option ED_NO_MIIBUS, which causes the `ed' driver to be
> > built without support for miibus PHYs. Most ed cards don't need
> > miibus support, so it's useful to be able to avoid the bloat of
> > all the mii devices for small fixed-purpose kernels.
>
> This is actually a bug in miibus. There should not be references into the
> bowels of the miibus code. ed should be able to call the methods when
> required, and that is the only time it would depend on it. And it would be
> able to fail at runtime, not compile time. Alternatively you could kldload
> the miibus code and it would automagically work.
As a specific example, consider:
static void
ed_tick(arg)
void *arg;
{
struct ed_softc *sc = arg;
struct mii_data *mii;
int s;
if (sc->gone) {
callout_handle_init(&sc->tick_ch);
return;
}
s = splimp();
if (sc->miibus != NULL) {
mii = device_get_softc(sc->miibus);
mii_tick(mii);
}
sc->tick_ch = timeout(ed_tick, sc, hz);
splx(s);
}
This should be something along the lines of:
static void
ed_tick(arg)
void *arg;
{
struct ed_softc *sc = arg;
int s;
if (sc->gone) {
callout_handle_init(&sc->tick_ch);
return;
}
s = splimp();
if (sc->miibus != NULL)
MII_TICK(sc->miibus);
sc->tick_ch = timeout(ed_tick, sc, hz);
splx(s);
}
This requires no compile-time or link-time dependencies on the miibus module.
There should be *NO* mii_xxx() calls in drivers, and no
"struct mii_data *mii;" and no "mii = device_get_softc(sc->miibus);"
code either. This is the very layering violation that newbus exists to
prevent.
I am not complaining about your change, just pointing out that the
implemenation needs more work to fit cleanly into the system.
Cheers,
-Peter
--
Peter Wemm - peter@FreeBSD.org; peter@yahoo-inc.com; peter@netplex.com.au
"All of this is for nothing if we don't go to the stars" - JMS/B5
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