Re: [PATCH 1/3] net: ethoc: don't advertise gigabit speed onattached PHY

From: Ben Hutchings
Date: Mon Jan 27 2014 - 05:18:42 EST


On Mon, 2014-01-27 at 07:59 +0400, Max Filippov wrote:
> OpenCores 10/100 Mbps MAC does not support speeds above 100 Mbps, but does
> not disable advertisement when PHY supports them. This results in
> non-functioning network when the MAC is connected to a gigabit PHY connected
> to a gigabit switch.
>
> The fix is to disable gigabit speed advertisement on attached PHY
> unconditionally.
>
> Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
> ---
> drivers/net/ethernet/ethoc.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/ethernet/ethoc.c b/drivers/net/ethernet/ethoc.c
> index 4de8cfd..0aa1a05 100644
> --- a/drivers/net/ethernet/ethoc.c
> +++ b/drivers/net/ethernet/ethoc.c
> @@ -712,6 +712,8 @@ static int ethoc_open(struct net_device *dev)
> netif_start_queue(dev);
> }
>
> + priv->phy->advertising &= ~(ADVERTISED_1000baseT_Full |
> + ADVERTISED_1000baseT_Half);
> phy_start(priv->phy);
> napi_enable(&priv->napi);
>

This is not sufficient to disable gigabit speeds; the supported mask
should also be limited. And it should be done even before the net
device is registered.

Rather than poking into the phy_device structure directly from this
driver, I think you should add a function in phylib for this purpose.

Ben.

--
Ben Hutchings
If at first you don't succeed, you're doing about average.

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