On Thu, 2012-08-16 at 19:15 +0000, Jiang Wang wrote:
> Hi Michael,
>
> I just checked the code for netif_carrier_off(), and it will return if
> the dev is not initialized (registered) as follows:
>
> void netif_carrier_off(struct net_device *dev)
> {
> if (!test_and_set_bit(__LINK_STATE_NOCARRIER, &dev->state)) {
> if (dev->reg_state == NETREG_UNINITIALIZED)
> return;
> linkwatch_fire_event(dev);
> }
> }
>
> So linkwatch_fire_event should not fire in this case, right? Thanks
> for the quick response.
>
Yes, you're right. Your patch should not cause any problem then.
But I still don't understand what problem you're trying to solve. The
link status from ethtool is determined by bnx2_get_link() and it should
always return link down before bnx2_open() is called. Can you please
elborate? Thanks.
> Regards,
>
> Jiang
>
> -------------------------------------
> Jiang Wang
> Member of Technical Staff
> Riverbed Technology
> Tel: (408) 522-5109
> Email: jiang.w...@riverbed.com
> www.riverbed.com
>
>
> -----Original Message-----
> From: Michael Chan [mailto:mc...@broadcom.com]
> Sent: Thursday, August 16, 2012 11:57 AM
> To: Jiang Wang
> Cc: net...@vger.kernel.org; linux-kernel@vger.kernel.org; Chaitanya Lala;
> Francis St. Amant; Jiang Wang
> Subject: Re: [PATCH] bnx2: turn off the network statck during initialization
>
> On Thu, 2012-08-16 at 11:21 -0700, Jiang Wang wrote:
> > The initialization state of bnx2 driver is wrong. It does not turn of
> > the Linux network stack using netif_carrier_off. This may lead to
> > inconsistent report from ethtool as the link is up but speed is
> > unknown when the cable is not plugged in.
> >
> > E.g.
> > Speed: Unknown! (0)<--------------------------------------
> > Duplex: Half <--------------------------------------
> > MDI: Unknown! (0)
> > Port: Twisted Pair
> > PHYAD: 1
> > Transceiver: internal
> > Auto-negotiation: on
> > Supports Wake-on: g
> > Wake-on: d
> > Link detected: yes <---------------------------------------
> >
> > This patches fixed the problem by turning off the network stack during
> > initialization.
> >
> > Signed-off-by: Jiang Wang <jw...@riverbed.com>
> > ---
> > drivers/net/ethernet/broadcom/bnx2.c | 4 ++++
> > 1 files changed, 4 insertions(+), 0 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/broadcom/bnx2.c
> > b/drivers/net/ethernet/broadcom/bnx2.c
> > index ac7b744..ce4548d 100644
> > --- a/drivers/net/ethernet/broadcom/bnx2.c
> > +++ b/drivers/net/ethernet/broadcom/bnx2.c
> > @@ -8463,6 +8463,10 @@ bnx2_init_one(struct pci_dev *pdev, const struct
> > pci_device_id *ent)
> > dev->features |= dev->hw_features;
> > dev->priv_flags |= IFF_UNICAST_FLT;
> >
> > + /* tell the stack to leave us alone until bnx2_open() is called */
> > + netif_carrier_off(dev);
>
> We have tried this before and this didn't work. netif_carrier_off() calls
> linkwatch_fire_event() to schedule the event. If
> register_netdev() fails for whatever reason, the netdev will be freed but the
> link_watch event may still be scheduled.
>
> Calling netif_carrier_off() after register_netdev() returns successfully also
> may not work as it will race with bnx2_open() which enables IRQ.
> An linkup IRQ can happen at time and we may end up with the wrong carrier
> state because of the race condition.
>
> > + netif_stop_queue(dev);
> > +
> > if ((rc = register_netdev(dev))) {
> > dev_err(&pdev->dev, "Cannot register net device\n");
> > goto error;
>
>
>
>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
