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.
Regards,
Jiang
-------------------------------------
Jiang Wang
Member of Technical Staff
Riverbed Technology
Tel: (408) 522-5109
Email: [email protected]
www.riverbed.com
-----Original Message-----
From: Michael Chan [mailto:[email protected]]
Sent: Thursday, August 16, 2012 11:57 AM
To: Jiang Wang
Cc: [email protected]; [email protected]; 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 <[email protected]>
> ---
> 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;
--
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