Re: when the MTU interface is modified, the promiscuous mode isreset in gianfar driver

[David Miller]

From: chikazawa.akifu@xxxxxxxxxxxxxx (近沢 哲史)
Date: Mon, 27 Aug 2012 17:38:34 +0900

>  I am using the gianfar ethernet driver. I am having a problem with the
>  interface settings.
>  Under promiscuous mode, when the MTU interface is modified, the promiscuous
>  mode setting is turned off in gianfar driver when it should not be.
> The details are as follows:
>  After changing MTU with ifconfig, I could see that the interface flag of
>  eth0 is still PROMISC.
>  However, when I checked value of RCTL register with ethtool, PROM bit of
>  RTCL register is cleared.
>  It seems to be cause that is the gfar_init_mac() function, it doesn't set
>  the PROM bit after the interface MTU is changed.
>  This problem was detected on linux-2.6.32.2, but it seems to same on
>  linux-3.6.0-rc3.
> Is this behavior on purpose?
> 
> I also attach the amended file,I think it would be so.
> 
> Signed-off-by: Akifumi Chikazawa <chikazawa.akifu@xxxxxxxxxxxxxx>

It seems like we also lose all of the multicast configurations as
well.

Therefore, the thing to do is to simply call gfar_set_multi() at the
appropriate location.  That will take care of both the promiscuous
bit, as well as the multicast addresses.

You can then remove some of the code in gfar_init_mac() that does
things like gfar_clear_exact_match(), because gfar_set_multi() will
take care of that if necessary.
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