Re: [PATCH 4.1 11/56] mvneta: add forgotten initialization of autonegotiation bits

[Stas Sergeev]

08.07.2015 20:36, Greg Kroah-Hartman ÐÐÑÐÑ:
> On Wed, Jul 08, 2015 at 08:10:46PM +0300, Stas Sergeev wrote:
> > 08.07.2015 10:35, Greg Kroah-Hartman ÐÐÑÐÑ:
> > > 4.1-stable review patch.  If anyone has any objections, please let me know.
> > >
> > > ------------------
> > >
> > > From: Stas Sergeev <stsp@xxxxxxx>
> > >
> > > [ Upstream commit 538761b794c1542f1c6e31eadd9d7aae118889f7 ]
> > >
> > > The commit 898b2970e2c9 ("mvneta: implement SGMII-based in-band link state
> > > signaling")
> > > changed mvneta_adjust_link() so that it does not clear the auto-negotiation
> > > bits in MVNETA_GMAC_AUTONEG_CONFIG register. This was necessary for
> > > auto-negotiation mode to work.
> > > Unfortunately I haven't checked if these bits are ever initialized.
> > > It appears they are not.
> > > This patch adds the missing initialization of the auto-negotiation bits
> > > in the MVNETA_GMAC_AUTONEG_CONFIG register.
> > > It fixes the following regression:
> > > https://www.mail-archive.com/netdev@xxxxxxxxxxxxxxx/msg67928.html
> > >
> > > Since the patch was tested to fix a regression, it should be applied to
> > > stable tree.
> > >
> > > Tested-by: Arnaud Ebalard <arno@xxxxxxxxxxxx>
> > >
> > > CC: Thomas Petazzoni <thomas.petazzoni@xxxxxxxxxxxxxxxxxx>
> > > CC: Florian Fainelli <f.fainelli@xxxxxxxxx>
> > > CC: netdev@xxxxxxxxxxxxxxx
> > > CC: linux-kernel@xxxxxxxxxxxxxxx
> > > CC: stable@xxxxxxxxxxxxxxx
> > >
> > > Signed-off-by: Stas Sergeev <stsp@xxxxxxxxxxxxxxxxxxxxx>
> > > Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> > > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> > > ---
> > >   drivers/net/ethernet/marvell/mvneta.c |    6 ++++++
> > >   1 file changed, 6 insertions(+)
> > >
> > > --- a/drivers/net/ethernet/marvell/mvneta.c
> > > +++ b/drivers/net/ethernet/marvell/mvneta.c
> > > @@ -1013,6 +1013,12 @@ static void mvneta_defaults_set(struct m
> > >   		val = mvreg_read(pp, MVNETA_GMAC_CLOCK_DIVIDER);
> > >   		val |= MVNETA_GMAC_1MS_CLOCK_ENABLE;
> > >   		mvreg_write(pp, MVNETA_GMAC_CLOCK_DIVIDER, val);
> > > +	} else {
> > > +		val = mvreg_read(pp, MVNETA_GMAC_AUTONEG_CONFIG);
> > > +		val &= ~(MVNETA_GMAC_INBAND_AN_ENABLE |
> > > +		       MVNETA_GMAC_AN_SPEED_EN |
> > > +		       MVNETA_GMAC_AN_DUPLEX_EN);
> > > +		mvreg_write(pp, MVNETA_GMAC_AUTONEG_CONFIG, val);
> > >   	}
> > >   	mvneta_set_ucast_table(pp, -1);
> > Hi Greg.
> >
> > Another problem was reported:
> > https://lkml.org/lkml/2015/7/8/865
> >
> > So, while the above patch is correct and fixes what
> > it should, the original patch has more problems to deal
> > with. Maybe for stable it would be better to just revert
> > the whole thing?
> No, you will have to fix this in Linus's tree, right?  So I'll take the
> patch that you get into there when that happens, I don't want to diverge
> from what is in that tree.
For Linus tree I am planning a new DT property to explicitly
enable the inband status. I don't see any quick fix suitable for
-stable, and new DT property will likely not be quickly accepted.
If you don't want a revert, then the stable will likely have that
regression for quite long, that's the warning.
OTOH, the revert will remove the support for my board, so I
won't be able to even test it, which is also not perfect.
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