[Intel-wired-lan] [PATCH v2] e1000e: move force SMBUS near the end of enable_ulp function

Hui Wang hui.wang at canonical.com
Fri May 17 09:45:36 UTC 2024


On 5/17/24 13:45, Paul Menzel wrote:
> Dear Hui,
>
>
> Thank you for your patch.
>
> Am 08.05.24 um 14:06 schrieb Hui Wang:
>> The commit 861e8086029e ("e1000e: move force SMBUS from enable ulp
>> function to avoid PHY loss issue") introduces a regression on
>> CH_MTP_I219_LM18 (PCIID: 0x8086550A). Without the referred commit, the
>
> *P*CH
>
>> ethernet works well after suspend and resume, but after applying the
>> commit, the ethernet couldn't work anymore after the resume and the
>> dmesg shows that the NIC Link changes to 10Mbps (1000Mbps originally):
>
> 1.  s/Link/link/
> 2.  “couldn’t work” means the reduced bandwidth?
On my side, once the link changes to 10Mbps, I couldn't ping the machine 
anymore. And as you said, it probably has sth to do with switch/router 
configuration.
> 3. Please add a blank line and maybe indent the past with four spaces.
>
>> [   43.305084] e1000e 0000:00:1f.6 enp0s31f6: NIC Link is Up 10 Mbps 
>> Full Duplex, Flow Control: Rx/Tx
>>
>> Without the commit, the force SMBUS code will not be executed if
>> "return 0" or "goto out" is executed in the enable_ulp(), and in my
>> case, the "goto out" is executed since FWSM_FW_VALID is set. But after
>> applying the commit, the force SMBUS code will be ran unconditionally.
>>
>> Here move the force SMBUS code back to enable_ulp() and put it
>> immediate ahead of hw->phy.ops.release(hw), this could allow the
>
> immediate*l*?
>
>> longest settling time as possible for interface in this function and
>> doesn't change the original code logic.
>
> Re-ordering code to achieve some waiting time sounds like, it’s not 
> 100 % sure, that the problem won’t occur again?

Actually this patch not only adds the waiting time, but also restore the 
original code logic:

  original: On a machine with the CSME, the SMBUS will not be forced, 
accordingly the SMBUS will not be unforced after resume.

  wrong: On a machine with the CSME, the SMBUS is forced, but the SMBUS 
is not unforced after resume, there is an unbalance. My patch could fix 
this case.


>
> Could you please document your test system?
Lenovo Thinkpad P16Gen2 with ethernet card:

00:1f.6 Ethernet controller [0200]: Intel Corporation Device [8086:550a] (rev 20)

>
> Just a side note: Booting Linux 6.9-rc5+ *with kexec* on Supermicro 
> Super Server/X13SAE, BIOS 2.0 10/17/2022 with the network device 
> below, it also came up only with 10 Mbps and Ethernet did not work, 
> for example `ping`. I conjectured though, that the non-working part 
> was due to the switch configuration not allowing 10 Mbps.
>
>     00:1f.6 Ethernet controller [0200]: Intel Corporation Ethernet 
> Connection (17) I219-LM [8086:1a1c] (rev 11)
>
My test and result are same as yours.

Thanks.

> I didn’t find the time to further analyze and report the issue.
>
> Also could this also be related to the regression reported by the 
> kernel test robot [1]?
>
>     00:19.0 Ethernet controller: Intel Corporation Ethernet Connection 
> (3) I218-V (rev 03)
>
>
>> Fixes: 861e8086029e ("e1000e: move force SMBUS from enable ulp 
>> function to avoid PHY loss issue")
>> Signed-off-by: Hui Wang <hui.wang at canonical.com>
>> Acked-by: Vitaly Lifshits <vitaly.lifshits at intel.com>
>> Tested-by: Naama Meir <naamax.meir at linux.intel.com>
>> Signed-off-by: Tony Nguyen <anthony.l.nguyen at intel.com>
>> ---
>> In the v2:
>>   Change "this commit" to "the referred commit" in the commit header
>>   Fix a potential infinite loop if ret_val is not zero
>>     drivers/net/ethernet/intel/e1000e/ich8lan.c | 22 
>> +++++++++++++++++++++
>>   drivers/net/ethernet/intel/e1000e/netdev.c  | 18 -----------------
>>   2 files changed, 22 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c 
>> b/drivers/net/ethernet/intel/e1000e/ich8lan.c
>> index f9e94be36e97..2e98a2a0bead 100644
>> --- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
>> +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
>> @@ -1225,6 +1225,28 @@ s32 e1000_enable_ulp_lpt_lp(struct e1000_hw 
>> *hw, bool to_sx)
>>       }
>>     release:
>> +    /* Switching PHY interface always returns MDI error
>> +     * so disable retry mechanism to avoid wasting time
>> +     */
>> +    e1000e_disable_phy_retry(hw);
>> +
>> +    /* Force SMBus mode in PHY */
>> +    ret_val = e1000_read_phy_reg_hv_locked(hw, CV_SMB_CTRL, &phy_reg);
>> +    if (ret_val) {
>> +        e1000e_enable_phy_retry(hw);
>> +        hw->phy.ops.release(hw);
>> +        goto out;
>> +    }
>> +    phy_reg |= CV_SMB_CTRL_FORCE_SMBUS;
>> +    e1000_write_phy_reg_hv_locked(hw, CV_SMB_CTRL, phy_reg);
>> +
>> +    e1000e_enable_phy_retry(hw);
>> +
>> +    /* Force SMBus mode in MAC */
>> +    mac_reg = er32(CTRL_EXT);
>> +    mac_reg |= E1000_CTRL_EXT_FORCE_SMBUS;
>> +    ew32(CTRL_EXT, mac_reg);
>> +
>>       hw->phy.ops.release(hw);
>>   out:
>>       if (ret_val)
>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c 
>> b/drivers/net/ethernet/intel/e1000e/netdev.c
>> index 3692fce20195..cc8c531ec3df 100644
>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
>> @@ -6623,7 +6623,6 @@ static int __e1000_shutdown(struct pci_dev 
>> *pdev, bool runtime)
>>       struct e1000_hw *hw = &adapter->hw;
>>       u32 ctrl, ctrl_ext, rctl, status, wufc;
>>       int retval = 0;
>> -    u16 smb_ctrl;
>>         /* Runtime suspend should only enable wakeup for link changes */
>>       if (runtime)
>> @@ -6697,23 +6696,6 @@ static int __e1000_shutdown(struct pci_dev 
>> *pdev, bool runtime)
>>               if (retval)
>>                   return retval;
>>           }
>> -
>> -        /* Force SMBUS to allow WOL */
>> -        /* Switching PHY interface always returns MDI error
>> -         * so disable retry mechanism to avoid wasting time
>> -         */
>> -        e1000e_disable_phy_retry(hw);
>> -
>> -        e1e_rphy(hw, CV_SMB_CTRL, &smb_ctrl);
>> -        smb_ctrl |= CV_SMB_CTRL_FORCE_SMBUS;
>> -        e1e_wphy(hw, CV_SMB_CTRL, smb_ctrl);
>> -
>> -        e1000e_enable_phy_retry(hw);
>> -
>> -        /* Force SMBus mode in MAC */
>> -        ctrl_ext = er32(CTRL_EXT);
>> -        ctrl_ext |= E1000_CTRL_EXT_FORCE_SMBUS;
>> -        ew32(CTRL_EXT, ctrl_ext);
>>       }
>>         /* Ensure that the appropriate bits are set in LPI_CTRL
>
>
> Kind regards,
>
> Paul
>
>
> [1]: 
> https://lore.kernel.org/intel-wired-lan/202405150942.f9b873b1-oliver.sang@intel.com/
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