[Intel-wired-lan] [PATCH] e1000e: Power cycle phy on PM resume

[Kai-Heng Feng]

Hi Paul,

> On Sep 23, 2020, at 21:28, Paul Menzel <pmenzel at molgen.mpg.de> wrote:
> 
> Dear Kai-Heng,
> 
> 
> Am 23.09.20 um 09:47 schrieb Kai-Heng Feng:
>> We are seeing the following error after S3 resume:
>> [  704.746874] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
>> [  704.844232] e1000e 0000:00:1f.6 eno1: MDI Write did not complete
>> [  704.902817] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
>> [  704.903075] e1000e 0000:00:1f.6 eno1: reading PHY page 769 (or 0x6020 shifted) reg 0x17
>> [  704.903281] e1000e 0000:00:1f.6 eno1: Setting page 0x6020
>> [  704.903486] e1000e 0000:00:1f.6 eno1: writing PHY page 769 (or 0x6020 shifted) reg 0x17
>> [  704.943155] e1000e 0000:00:1f.6 eno1: MDI Error
>> ...
>> [  705.108161] e1000e 0000:00:1f.6 eno1: Hardware Error
>> Since we don't know what platform firmware may do to the phy, so let's
>> power cycle the phy upon system resume to resolve the issue.
> 
> Is there a bug report or list thread for this issue?

No. That's why I sent a patch to start discussion :)

> 
>> Signed-off-by: Kai-Heng Feng <kai.heng.feng at canonical.com>
>> ---
>>  drivers/net/ethernet/intel/e1000e/netdev.c | 2 ++
>>  1 file changed, 2 insertions(+)
>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
>> index 664e8ccc88d2..c2a87a408102 100644
>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>> @@ -6968,6 +6968,8 @@ static __maybe_unused int e1000e_pm_resume(struct device *dev)
>>  	    !e1000e_check_me(hw->adapter->pdev->device))
>>  		e1000e_s0ix_exit_flow(adapter);
>>  +	e1000_power_down_phy(adapter);
>> +
>>  	rc = __e1000_resume(pdev);
>>  	if (rc)
>>  		return rc;
> 
> How much does this increase the resume time?

I didn't measure it. Because for me it's more important to have a working device.

Does it have a noticeable impact on your system's resume time?

Kai-Heng

> 
> 
> Kind regards,
> 
> Paul
>