svn commit: r187978 - user/thompsa/usb/sys/dev/usb2/ethernet

[Pyun YongHyeon]

On Sun, Feb 01, 2009 at 09:52:18PM -0700, M. Warner Losh wrote:
> In message: <20090202044416.GC43513 at michelle.cdnetworks.co.kr>
>             Pyun YongHyeon <pyunyh at gmail.com> writes:
> : On Sun, Feb 01, 2009 at 08:36:18PM -0700, M. Warner Losh wrote:
> : > In message: <20090201213749.GJ32503 at citylink.fud.org.nz>
> : >             Andrew Thompson <thompsa at FreeBSD.org> writes:
> : > : On Sun, Feb 01, 2009 at 02:28:08PM -0700, M. Warner Losh wrote:
> : > : > In message: <200902010650.n116obU1045871 at svn.freebsd.org>
> : > : >             Andrew Thompson <thompsa at FreeBSD.org> writes:
> : > : > : +	locked = mtx_owned(&sc->sc_mtx);
> : > : > : +	if (!locked)
> : > : > : +		AUE_LOCK(sc);
> : > : > 
> : > : > You do know this is racy, right?
> : > : 
> : > : Yea... It only get called unlocked during mii probe+attach so its fine.
> : > : I havnt actaully checked if its ok to hold a mutex during
> : > : mii_phy_probe() which would make this go away.
> : > 
> : > You hold GIANT when probe+attach, which means I think you can't
> : 
> : AFAIK this is not true on USB2 and I think this is reason why
> : it have to lock/unlock dance in probe/attach.
> 
> It is a newbus requirement that all probe/attach routines have to be
> called with GIANT held.
> 

If this can be done on USB2 it would greatly simplify MII attach
part as well as locks used in MII access routines in all USB2
ethernet drivers. I vaguely remember I asked for this to HPS, but
he seem to forget about it.