-----Original Message-----
From: Kevin Traynor <ktray...@redhat.com>
Sent: Tuesday, 20 December, 2022 11:48 PM
To: Mah, Yock Gen <yock.gen....@intel.com>; IOTG DPDK Ref App
<iotg.dpdk.ref....@intel.com>; Zhang, Qi Z <qi.z.zh...@intel.com>; Taripin,
Samuel <samuel.tari...@intel.com>
Cc: dev@dpdk.org
Subject: Re: [PATCH v2] IGC: Remove I225_I_PHY_ID checking
On 19/10/2022 09:34, Kevin Traynor wrote:
> On 18/10/2022 23:45, Mah, Yock Gen wrote:
>>
>>
>> -----Original Message-----
>> From: Kevin Traynor <ktray...@redhat.com>
>> Sent: Tuesday, 18 October, 2022 8:54 PM
>> To: Mah, Yock Gen <yock.gen....@intel.com>; IOTG DPDK Ref App
>> <iotg.dpdk.ref....@intel.com>; Zhang, Qi Z <qi.z.zh...@intel.com>
>> Cc: dev@dpdk.org
>> Subject: Re: [PATCH v2] IGC: Remove I225_I_PHY_ID checking
>>
>> On 12/10/2022 09:39, Kevin Traynor wrote:
>>> On 12/10/2022 08:45, Mah, Yock Gen wrote:
>>>>
>>>>
>>>> -----Original Message-----
>>>> From: Kevin Traynor <ktray...@redhat.com>
>>>> Sent: Tuesday, 11 October, 2022 7:05 PM
>>>> To: IOTG DPDK Ref App <iotg.dpdk.ref....@intel.com>; Zhang, Qi Z
>>>> <qi.z.zh...@intel.com>
>>>> Cc: dev@dpdk.org
>>>> Subject: Re: [PATCH v2] IGC: Remove I225_I_PHY_ID checking
>>>>
>>>> On 31/08/2022 23:51, iotg.dpdk.ref....@intel.com wrote:
>>>>> From: NSWE SWS DPDK Dev <iotg.dpdk.ref....@intel.com>
>>>>>
>>>>> i225 devices have only one PHY vendor. There is unnecessary to
>>>>> check _I_PHY_ID during the link establishment and auto-negotiation
>>>>> process, the checking also caused devices like i225-IT failed.
>>>>> This patch is to remove the mentioned unnecessary checking.
>>>>>
>>>>> Cc: sta...@dpdk.org
>>>>> Signed-off-by: NSWE SWS DPDK Dev <iotg.dpdk.ref....@intel.com>
>>>>> ---
>>>>> drivers/net/igc/base/igc_i225.c | 15 ++-------------
>>>>> drivers/net/igc/base/igc_phy.c | 6 ++----
>>>>> 2 files changed, 4 insertions(+), 17 deletions(-)
>>>>>
>>>>> diff --git a/drivers/net/igc/base/igc_i225.c
>>>>> b/drivers/net/igc/base/igc_i225.c index 5f3d535490..af26602afb
>>>>> 100644
>>>>> --- a/drivers/net/igc/base/igc_i225.c
>>>>> +++ b/drivers/net/igc/base/igc_i225.c
>>>>> @@ -173,19 +173,8 @@ static s32 igc_init_phy_params_i225(struct igc_hw
>>>>> *hw)
>>>>> phy->ops.write_reg = igc_write_phy_reg_gpy;
>>>>>
>>>>> ret_val = igc_get_phy_id(hw);
>>>>> - /* Verify phy id and set remaining function pointers */
>>>>> - switch (phy->id) {
>>>>> - case I225_I_PHY_ID:
>>>>> - case I226_LM_PHY_ID:
>>>>> - phy->type = igc_phy_i225;
>>>>> - phy->ops.set_d0_lplu_state = igc_set_d0_lplu_state_i225;
>>>>> - phy->ops.set_d3_lplu_state = igc_set_d3_lplu_state_i225;
>>>>
>>>>> - The commit log says it is removing a check on the ID, but it does not
>>>>> say why these function pointers are being removed.
>>>>
>>>>> - Why are they removed, were they not needed?
>>>>
>>>>
>>>> i225 devices have only one PHY vendor. There is no point checking
>>>> _I_PHY_ID during the link establishment and auto-negotiation process.
>>>>
>>>
>>> Right, that's clear about the vendor ID check. But it's not clear to
>>> me why the the resulting code like this:
>>>
>>> phy->type = igc_phy_i225;
>>>
>>> and not like this:
>>>
>>> phy->type = igc_phy_i225;
>>> phy->ops.set_d0_lplu_state = igc_set_d0_lplu_state_i225;
>>> phy->ops.set_d3_lplu_state = igc_set_d3_lplu_state_i225;
>>>
>>> So it is using dummy null functions instead:
>>> https://git.dpdk.org/dpdk/tree/drivers/net/igc/base/igc_phy.c#n61
>>>
>>> Do the device registers not need to be set anymore?
>>>
>>
>>> For main branch, it would be nice to have an answer to above.
>>
>>> It only adds a small readability benefit by removing some code branches,
>>> but does change functionality which adds risk, so I don't think it's a good
>>> candidate for stable branches.
>>
>> This is not only added readability, but to fix real world issue, we were
>> experiencing i225-IT not runnable issue without patching another case
>> checking as below:
>>
>> +++ b/drivers/net/igc/base/igc_phy.c
>> @@ -1881,6 +1881,7 @@ s32 igc_phy_force_speed_duplex_m88(struct igc_hw *hw)
>> case I210_I_PHY_ID:
>> /* fall-through */
>> case I225_I_PHY_ID:
>> + case I225_IT_PHY_ID:
>>
>> However, cleaner solution is to remove those unnecessary checking
>> completely as it does in kernel also
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/co
>> mmit/?id=7c496de538eebd8212dc2a3c9a468386b264d0d4
>>
>
> ok, you are correct that it is more than readability. I can apply but
> first it would be good if you can answer the original question and
> explain why the functionality is changed for I225_I_PHY_ID by removing
> the function pointers that set the registers.
>
>Hi, I didn't apply this to DPDK 21.11.3 because there was no explanation of
>why the registers were changing after asking multiple times.
I>f it is required for a later 21.11 LTS release, please send a backport to
stable mailing list with an updated commit message explaining the changes.
>thanks,
>Kevin.
Apology of the late reply, we were missed out your last message.
Yes, we will re-submit the patch for 21.11 LTS with clearer explanation.
Thanks,
Mah
>>>>> - /* TODO - complete with GPY PHY information */
>>>>> - break;
>>>>> - default:
>>>>> - ret_val = -IGC_ERR_PHY;
>>>>> - goto out;
>>>>> - }
>>>>> + phy->type = igc_phy_i225;
>>>>> +
>>>>>
>>>>> out:
>>>>> return ret_val;
>>>>> diff --git a/drivers/net/igc/base/igc_phy.c
>>>>> b/drivers/net/igc/base/igc_phy.c index 43bbe69bca..2906bae21a
>>>>> 100644
>>>>> --- a/drivers/net/igc/base/igc_phy.c
>>>>> +++ b/drivers/net/igc/base/igc_phy.c
>>>>> @@ -1474,8 +1474,7 @@ s32 igc_phy_setup_autoneg(struct igc_hw *hw)
>>>>> return ret_val;
>>>>> }
>>>>>
>>>>> - if ((phy->autoneg_mask & ADVERTISE_2500_FULL) &&
>>>>> - hw->phy.id == I225_I_PHY_ID) {
>>>>> + if (phy->autoneg_mask & ADVERTISE_2500_FULL) {
>>>>> /* Read the MULTI GBT AN Control Register - reg 7.32 */
>>>>> ret_val = phy->ops.read_reg(hw, (STANDARD_AN_REG_MASK <<
>>>>> MMD_DEVADDR_SHIFT) | @@
>>>>> -1615,8 +1614,7 @@ s32
>>>>> igc_phy_setup_autoneg(struct igc_hw *hw)
>>>>> ret_val = phy->ops.write_reg(hw, PHY_1000T_CTRL,
>>>>> mii_1000t_ctrl_reg);
>>>>>
>>>>> - if ((phy->autoneg_mask & ADVERTISE_2500_FULL) &&
>>>>> - hw->phy.id == I225_I_PHY_ID)
>>>>> + if (phy->autoneg_mask & ADVERTISE_2500_FULL)
>>>>> ret_val = phy->ops.write_reg(hw,
>>>>> (STANDARD_AN_REG_MASK <<
>>>>> MMD_DEVADDR_SHIFT) |
>>>>
>>>
>>
>
