linux-kernel - Re: [Intel-wired-lan] [PATCH v4] e1000e: Increase polling timeout on MDIC ready bit

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Date:   Wed, 30 Sep 2020 09:54:34 +0300
From:   Vitaly Lifshits <vitaly.lifshits@...el.com>
To:     Kai-Heng Feng <kai.heng.feng@...onical.com>,
        "Neftin, Sasha" <sasha.neftin@...el.com>
CC:     Jeff Kirsher <jeffrey.t.kirsher@...el.com>,
        Andrew Lunn <andrew@...n.ch>,
        "open list:NETWORKING DRIVERS" <netdev@...r.kernel.org>,
        open list <linux-kernel@...r.kernel.org>,
        "moderated list:INTEL ETHERNET DRIVERS" 
        <intel-wired-lan@...ts.osuosl.org>,
        Jakub Kicinski <kuba@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        "Nguyen, Anthony L" <anthony.l.nguyen@...el.com>
Subject: Re: [Intel-wired-lan] [PATCH v4] e1000e: Increase polling timeout on
 MDIC ready bit

On 9/29/2020 18:08, Kai-Heng Feng wrote:

Hello Kai-Heng,
> 
> 
>> On Sep 29, 2020, at 21:46, Neftin, Sasha <sasha.neftin@...el.com> wrote:
>>
>> Hello Kai-Heng,
>> On 9/29/2020 16:31, Kai-Heng Feng wrote:
>>> Hi Sasha,
>>>> On Sep 29, 2020, at 21:08, Neftin, Sasha <sasha.neftin@...el.com> wrote:
>>>>
>>>> On 9/28/2020 11:36, Kai-Heng Feng wrote:
>>>>> 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
>>>>> As Andrew Lunn pointed out, MDIO has nothing to do with phy, and indeed
>>>>> increase polling iteration can resolve the issue.
>>>>> This patch only papers over the symptom, as we don't really know the
>>>>> root cause of the issue. The most possible culprit is Intel ME, which
>>>>> may do its own things that conflict with software.
>>>>> Signed-off-by: Kai-Heng Feng <kai.heng.feng@...onical.com>
>>>>> ---
>>>>> v4:
>>>>>   - States that this patch just papers over the symptom.
>>>>> v3:
>>>>>   - Moving delay to end of loop doesn't save anytime, move it back.
>>>>>   - Point out this is quitely likely caused by Intel ME.
>>>>> v2:
>>>>>   - Increase polling iteration instead of powering down the phy.
>>>>>   drivers/net/ethernet/intel/e1000e/phy.c | 2 +-
>>>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>>> diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
>>>>> index e11c877595fb..e6d4acd90937 100644
>>>>> --- a/drivers/net/ethernet/intel/e1000e/phy.c
>>>>> +++ b/drivers/net/ethernet/intel/e1000e/phy.c
>>>>> @@ -203,7 +203,7 @@ s32 e1000e_write_phy_reg_mdic(struct e1000_hw *hw, u32 offset, u16 data)
>>>>>   	 * Increasing the time out as testing showed failures with
>>>>>   	 * the lower time out
>>>>>   	 */
>>>>> -	for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 3); i++) {
>>>>> +	for (i = 0; i < (E1000_GEN_POLL_TIMEOUT * 10); i++) {
>>>> As we discussed (many threads) - AMT/ME systems not supported on Linux as properly. I do not think increasing polling iteration will solve the problem. Rather mask it.
>>> I am aware of the status quo of no proper support on Intel ME.
>>>> I prefer you check option to disable ME vi BIOS on your system.
>>> We can't ask user to change the BIOS to accommodate Linux. So before a proper solution comes out, masking the problem is good enough for me.
>>> Until then, I'll carry it as a downstream distro patch.
>> What will you do with system that even after increasing polling time will run into HW error?
> 
> Hope we finally have proper ME support under Linux?
> 
> Kai-Heng
> 
>>> Kai-Heng
>>>>>   		udelay(50);
>>>>>   		mdic = er32(MDIC);
>>>>>   		if (mdic & E1000_MDIC_READY)
>>>> Thanks,
>>>> Sasha
>> Thanks,
>> Sasha
> 

On which device ID/platform do you see the issue? What is the Firmware 
version on your platform? What is the ME firmware version that you have?

I am asking these questions, since I know there is supposed to be a fix 
in the firmware to many issues that are related to ME and device 
interoperability.

Thanks,

Vitaly