netdev - Re: [PATCH] gianfar: fix bug caused by 87c288c6e9aa31720b72e2bc2d665e24e1653c3e

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Date:	Tue, 26 Jul 2011 14:21:19 +0200
From:	"Sebastian Pöhn" <sebastian.belden@...glemail.com>
To:	Jiri Pirko <jpirko@...hat.com>
Cc:	Linux Netdev <netdev@...r.kernel.org>
Subject: Re: [PATCH] gianfar: fix bug caused by
 87c288c6e9aa31720b72e2bc2d665e24e1653c3e

Am Dienstag, den 26.07.2011, 14:04 +0200 schrieb Jiri Pirko:
> Tue, Jul 26, 2011 at 01:13:41PM CEST, sebastian.belden@...glemail.com wrote:
> >Am Dienstag, den 26.07.2011, 12:46 +0200 schrieb Jiri Pirko:
> >> Tue, Jul 26, 2011 at 12:03:13PM CEST, sebastian.belden@...glemail.com wrote:
> >> >commit 87c288c6e9aa31720b72e2bc2d665e24e1653c3e "gianfar: do vlan cleanup" has two issues:
> >> ># permutation of rx and tx flags
> >> ># enabling vlan tag insertion by default (this leads to unusable connections on some configurations)
> >> 
> >> How so? What's causing that?
> >If you enable the VLINS bit of txctrl and do not alter the vlan tag
> >configuration of the NIC, every packet will get a all zero vlan tag
> >(0x8100 0000). If you run a network without vlan awareness all packets
> >will be ignored.
> 
> 
> Interesting hw... I would guess that if gfar_tx_vlan() is not called, no
> tag would be put there...
The Freescale documentation says in detail:

if(FCB has valid VLAN field)
	send packet with this one
else
	send packet with default vlan tag

default vlan tag = dfvlan register = 0x8100 0000 by default
> 
> >
> >In my configuration gianfar system <-> 3c59x system the 3com system
> >discards all packets received with the vlan tag.
> >> 
> >> >
> >> >If VLAN insertion is requested (via ethtool) it will be set at an other point ...
> >> >
> >> >Signed-off-by: Sebastian Poehn <sebastian.poehn@...den.com>
> >> >---
> >> >
> >> > drivers/net/gianfar.c |    6 +-----
> >> > 1 files changed, 1 insertions(+), 5 deletions(-)
> >> >
> >> >diff --git a/drivers/net/gianfar.c b/drivers/net/gianfar.c
> >> >index 835cd25..2659daa 100644
> >> >--- a/drivers/net/gianfar.c
> >> >+++ b/drivers/net/gianfar.c
> >> >@@ -388,12 +388,8 @@ static void gfar_init_mac(struct net_device *ndev)
> >> > 	if (priv->hwts_rx_en)
> >> > 		rctrl |= RCTRL_PRSDEP_INIT | RCTRL_TS_ENABLE;
> >> > 
> >> >-	/* keep vlan related bits if it's enabled */
> >> >-	if (ndev->features & NETIF_F_HW_VLAN_TX)
> >> >-		rctrl |= RCTRL_VLEX | RCTRL_PRSDEP_INIT;
> >> >-
> >> > 	if (ndev->features & NETIF_F_HW_VLAN_RX)
> >> >-		tctrl |= TCTRL_VLINS;
> >> >+		rctrl |= RCTRL_VLEX | RCTRL_PRSDEP_INIT;
> >> > 
> >> > 	/* Init rctrl based on our settings */
> >> > 	gfar_write(&regs->rctrl, rctrl);
> >> >
> >> >
> >> 
> >> If you really need that to be done, you should remove NETIF_F_HW_VLAN_TX
> >> from features (not hw_features) (never add it).
> >> 
> >The only thing I did is to let the vlan insertion disabled by default.
> >If someone wants it, it may be enabled via ethtool.
> >
> >


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