netdev - Re: [PATCH net-next] igb: reset PHY after recovering from PHY power down

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Message-ID: <4EE83A53.2030202@jp.fujitsu.com>
Date:	Wed, 14 Dec 2011 14:55:31 +0900
From:	Koki Sanagi <sanagi.koki@...fujitsu.com>
To:	"Wyborny, Carolyn" <carolyn.wyborny@...el.com>
CC:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
	"Kirsher, Jeffrey T" <jeffrey.t.kirsher@...el.com>,
	"Brandeburg, Jesse" <jesse.brandeburg@...el.com>,
	"Allan, Bruce W" <bruce.w.allan@...el.com>,
	"Skidmore, Donald C" <donald.c.skidmore@...el.com>,
	"Rose, Gregory V" <gregory.v.rose@...el.com>,
	"Waskiewicz Jr, Peter P" <peter.p.waskiewicz.jr@...el.com>,
	"Duyck, Alexander H" <alexander.h.duyck@...el.com>,
	"Ronciak, John" <john.ronciak@...el.com>,
	"e1000-devel@...ts.sourceforge.net" 
	<e1000-devel@...ts.sourceforge.net>,
	"davem@...emloft.net" <davem@...emloft.net>
Subject: Re: [PATCH net-next] igb: reset PHY after recovering from PHY power
 down

(2011/11/29 2:57), Wyborny, Carolyn wrote:
> 
> 
>> -----Original Message-----
>> From: Koki Sanagi [mailto:sanagi.koki@...fujitsu.com]
>> Sent: Wednesday, November 23, 2011 7:18 PM
>> To: netdev@...r.kernel.org; Kirsher, Jeffrey T; Brandeburg, Jesse;
>> Allan, Bruce W; Wyborny, Carolyn; Skidmore, Donald C; Rose, Gregory V;
>> Waskiewicz Jr, Peter P; Duyck, Alexander H; Ronciak, John; e1000-
>> devel@...ts.sourceforge.net
>> Cc: davem@...emloft.net
>> Subject: [PATCH net-next] igb: reset PHY after recovering from PHY power
>> down
>>
>> According to 82576_Datasheet.pdf, PHY setting is lost after PHY power
>> down.
>> So resetting PHY is needed when recovering from PHY power down to set a
>> default
>> setting to PHY register.
>>
>> Owing to this lack, NIC doesn't link up in some rare situation.
>> The situation I encountered is following.
>>
>>
>> 1.Both ports connect to switch.
>> +---------+           +--------+
>> |         |-----------|        |
>> | 82576NS |           | switch |
>> |         |-----------|        |
>> +---------+           +--------+
>>
>> 2.Detach both cables from switch.
>> +---------+           +--------+
>> |         |-------    |        |
>> | 82576NS |           | switch |
>> |         |-------    |        |
>> +---------+           +--------+
>>
>> 3.Detach one cable from one port.
>> +---------+           +--------+
>> |         |-------    |        |
>> | 82576NS |           | switch |
>> |         |           |        |
>> +---------+           +--------+
>>
>> 4.Attach that cable to the other port.(It means connecting directly each
>> port)
>> +---------+           +--------+
>> |         |-------+   |        |
>> | 82576NS |       |   | switch |
>> |         |-------+   |        |
>> +---------+           +--------+
>>
>> As a result, NIC doesn't link up sometimes.
>>
>> Signed-off-by: Koki Sanagi <sanagi.koki@...fujitsu.com>
>> ---
>> drivers/net/ethernet/intel/igb/igb_main.c |    1 +
>> 1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/igb/igb_main.c
>> b/drivers/net/ethernet/intel/igb/igb_main.c
>> index bd9b30e..4d4f065 100644
>> --- a/drivers/net/ethernet/intel/igb/igb_main.c
>> +++ b/drivers/net/ethernet/intel/igb/igb_main.c
>> @@ -2496,6 +2496,7 @@ static int igb_open(struct net_device *netdev)
>> 		goto err_setup_rx;
>>
>> 	igb_power_up_link(adapter);
>> +	igb_reset_phy(hw);
>>
>> 	/* before we allocate an interrupt, we must be ready to handle it.
>> 	 * Setting DEBUG_SHIRQ in the kernel makes it fire an interrupt
> 
> Hello,
> 
> This seems reasonable, however it would only cover cases where igb_open is being called.  It would be better to integrate the phy_reset call into igb_power_up_link, so that's the default. I can provide an alternate by end of the week.
> 

When will the alternate be provided ?

In addition, more general problem which this lack of reset causes is found.

Two machine have 82576NS and each NIC is connected directly each other.

+--------+                           +--------+
|        |                           |        |
|        +-------+           +-------+        |
|        |       |           |       |        |
|machineA|82576NS|-----------|82576NS|machineB|
|        |       |           |       |        |
|        +-------+           +-------+        |
|        |                           |        |
+--------+                           +--------+

When attaching and detaching a cable repeatedly on one side port,
that side port becomes not link up.

This is also fixed by adding resetting phy.

Thanks,
Koki Sanagi

> Thanks,
> 
> Carolyn
> 
> Carolyn Wyborny
> Linux Development
> LAN Access Division
> Intel Corporation
> 
> 
> 
> 


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