Date:	Wed, 30 Dec 2015 06:55:37 +0000
From:	"Tantilov, Emil S" <emil.s.tantilov@...el.com>
To:	zhuyj <zyjzyj2000@...il.com>,
	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
	"Nelson, Shannon" <shannon.nelson@...el.com>,
	"Wyborny, Carolyn" <carolyn.wyborny@...el.com>,
	"Skidmore, Donald C" <donald.c.skidmore@...el.com>,
	"Allan, Bruce W" <bruce.w.allan@...el.com>,
	"Ronciak, John" <john.ronciak@...el.com>,
	"Williams, Mitch A" <mitch.a.williams@...el.com>,
	"intel-wired-lan@...ts.osuosl.org" <intel-wired-lan@...ts.osuosl.org>,
	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"e1000-devel@...ts.sourceforge.net" 
	<e1000-devel@...ts.sourceforge.net>
CC:	"Viswanathan, Ven (Wind River)" <venkat.viswanathan@...driver.com>,
	"Shteinbock, Boris (Wind River)" <boris.shteinbock@...driver.com>,
	"Bourg, Vincent (Wind River)" <vincent.bourg@...driver.com>
Subject: RE: [Intel-wired-lan] [PATCH 2/2] ixgbe: restrict synchronization
 of link_up and speed

>-----Original Message-----
>From: zhuyj [mailto:zyjzyj2000@...il.com]
>Sent: Tuesday, December 29, 2015 6:49 PM
>To: Tantilov, Emil S; Kirsher, Jeffrey T; Brandeburg, Jesse; Nelson,
>Shannon; Wyborny, Carolyn; Skidmore, Donald C; Allan, Bruce W; Ronciak,
>John; Williams, Mitch A; intel-wired-lan@...ts.osuosl.org;
>netdev@...r.kernel.org; e1000-devel@...ts.sourceforge.net
>Cc: Viswanathan, Ven (Wind River); Shteinbock, Boris (Wind River); Bourg,
>Vincent (Wind River)
>Subject: Re: [Intel-wired-lan] [PATCH 2/2] ixgbe: restrict synchronization
>of link_up and speed
>
>On 12/30/2015 12:18 AM, Tantilov, Emil S wrote:
>>> -----Original Message-----
>>> From: Intel-wired-lan [mailto:intel-wired-lan-bounces@...ts.osuosl.org]
>On
>>> Behalf Of zyjzyj2000@...il.com
>>> Sent: Monday, December 28, 2015 6:32 PM
>>> To: Kirsher, Jeffrey T; Brandeburg, Jesse; Nelson, Shannon; Wyborny,
>>> Carolyn; Skidmore, Donald C; Allan, Bruce W; Ronciak, John; Williams,
>Mitch
>>> A; intel-wired-lan@...ts.osuosl.org; netdev@...r.kernel.org; e1000-
>>> devel@...ts.sourceforge.net
>>> Cc: Viswanathan, Ven (Wind River); Shteinbock, Boris (Wind River);
>Bourg,
>>> Vincent (Wind River)
>>> Subject: [Intel-wired-lan] [PATCH 2/2] ixgbe: restrict synchronization
>of
>>> link_up and speed
>>>
>>> From: Zhu Yanjun <yanjun.zhu@...driver.com>
>>>
>>> When the X540 NIC acts as a slave of some virtual NICs, it is very
>>> important to synchronize link_up and link_speed, such as a bonding
>>> driver in 802.3ad mode. When X540 NIC acts as an independent interface,
>>> it is not necessary to synchronize link_up and link_speed. That is,
>>> the time span between link_up and link_speed is acceptable.
>> What exactly do you mean by "time span between link_up and link_speed"?
>
>In the previous mail, I show you some ethtool logs. In these logs, there
>is some
>time with NIC up while speed is unknown. I think this "some time" is
>time span between
>link_up and link_speed. Please see the previous mail for details.

Was this when reporting the link state from check_link() (reading the LINKS
register) or reporting the adapter->link_speed?

>> Where is it you think the de-synchronization occurs?
>
>When a NIC interface acts as a slave, a flag "IFF_SLAVE" is set in
>netdevice struct.
>Before we enter this function, we check IFF_SLAVE flag. If this flag is
>set, we continue to check
>link_speed. If not, this function is executed whether this link_speed is
>unknown or not.

I can already see this in your patch. I was asking about the reason why your 
change is needed.

>>
>>> Signed-off-by: Zhu Yanjun <yanjun.zhu@...driver.com>
>>> ---
>>> drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |    9 ++++++++-
>>> 1 file changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>>> b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>>> index ace21b9..1bb6056 100644
>>> --- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>>> +++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
>>> @@ -6436,8 +6436,15 @@ static void ixgbe_watchdog_link_is_up(struct
>>> ixgbe_adapter *adapter)
>>> 	 * time. To X540 NIC, there is a time span between link_up and
>>> 	 * link_speed. As such, only continue if link_up and link_speed are
>>> 	 * ready to X540 NIC.
>>> +	 * The time span between link_up and link_speed is very important
>>> +	 * when the X540 NIC acts as a slave in some virtual NICs, such as
>>> +	 * a bonding driver in 802.3ad mode. When X540 NIC acts as an
>>> +	 * independent interface, it is not necessary to synchronize link_up
>>> +	 * and link_speed.
>>> +	 * In the end, not continue if (X540 NIC && SLAVE && link_speed
>>> UNKNOWN)
>> This is a patch on top of your previous patch which I don't think was
>applied,
>> so this is not going to apply cleanly.
>>
>>> 	 */
>>> -	if (hw->mac.type == ixgbe_mac_X540)
>>> +	if ((hw->mac.type == ixgbe_mac_X540) &&
>>> +	    (netdev->flags & IFF_SLAVE))
>>> 		if (link_speed == IXGBE_LINK_SPEED_UNKNOWN)
>>> 			return;
>> If you were to enter ixgbe_watchdog_link_is_up() with unknown speed, then
>I would
>> assume that you also have a dmesg that shows:
>> "NIC Link is Up unknown speed"
>>
>> by the interface you use in the bond?
>Sure. There is a dmesg log from the customer.
>"
>...
>2015-10-05T06:14:34.350 controller-0 kernel: info bonding: bond0: link
>status definitely up for interface eth0, 0 Mbps full duplex.

This message is from the bonding driver not from ixgbe.

In your patch you are adding a check for unknown link to ixgbe_watchdog_link_is_up()
if that condition was true then you should also see "unknown link" being reported by ixgbe.

Thanks,
Emil

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