Re: [PATCH] r8169: fix broken register writes

[Al Viro <viro@ZenIV.linux.org.uk>]

On Sun, Mar 28, 2010 at 11:19:24PM +0100, Al Viro wrote:

> > > Thanks Fran?ois.  Which hardware have you tested this on so far ?
> > 
> > 10ec:8169 (rev 10) / RTL8169sb/8110sb / XID 10000000
> > 
> > Timo's is a 10ec:8167 / RTL8169sc/8110sc / XID 18000000. He only tested
> > the MAC[04] part.
> 
> FWIW, XID18000000 here (J7F4) loses MAC4 on shutdown; hadn't tested the patch
> yet.  2.6.26 (on that box) and 2.6.31 (on identical mb) work, 2.6.33 doesn't.
> I suspect that bisect would lead to commit cc098dc70 (i.e. the place where we
> started to set address on shutdown).  One more data point: ifconfig hw ether
> done under 2.6.26 did restore the address.  And that's the same function,
> isn't it?

As the matter of fact, ifconfig eth0 hw ether .... ends up zeroing upper
32 bits on old kernels once in a while.

What orders accesses as seen by PCI bus in
        RTL_W8(Cfg9346, Cfg9346_Unlock);
        RTL_W32(MAC0, low);
        RTL_W32(MAC4, high);
        RTL_W8(Cfg9346, Cfg9346_Lock);
anyway, and don't we need mmiowb() or two in there?