-----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/commit/?id=7c496de538eebd8212dc2a3c9a468386b264d0d4
>>> - /* 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) |
>>
>
