From: Kevin Traynor <ktraynor@redhat.com>
To: "Mah, Yock Gen" <yock.gen.mah@intel.com>,
IOTG DPDK Ref App <iotg.dpdk.ref.app@intel.com>,
"Zhang, Qi Z" <qi.z.zhang@intel.com>,
"Taripin, Samuel" <samuel.taripin@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [PATCH v2] IGC: Remove I225_I_PHY_ID checking
Date: Wed, 19 Oct 2022 09:34:07 +0100 [thread overview]
Message-ID: <d5a25c96-8b8e-ac63-c820-c594b5df3841@redhat.com> (raw)
In-Reply-To: <MN2PR11MB420662DD09B256FE0A6CAA41D9289@MN2PR11MB4206.namprd11.prod.outlook.com>
On 18/10/2022 23:45, Mah, Yock Gen wrote:
>
>
> -----Original Message-----
> From: Kevin Traynor <ktraynor@redhat.com>
> Sent: Tuesday, 18 October, 2022 8:54 PM
> To: Mah, Yock Gen <yock.gen.mah@intel.com>; IOTG DPDK Ref App <iotg.dpdk.ref.app@intel.com>; Zhang, Qi Z <qi.z.zhang@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 <ktraynor@redhat.com>
>>> Sent: Tuesday, 11 October, 2022 7:05 PM
>>> To: IOTG DPDK Ref App <iotg.dpdk.ref.app@intel.com>; Zhang, Qi Z
>>> <qi.z.zhang@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.app@intel.com wrote:
>>>> From: NSWE SWS DPDK Dev <iotg.dpdk.ref.app@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: stable@dpdk.org
>>>> Signed-off-by: NSWE SWS DPDK Dev <iotg.dpdk.ref.app@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
>
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.
>>>> - /* 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) |
>>>
>>
>
next prev parent reply other threads:[~2022-10-19 8:34 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-29 8:14 [PATCH] " iotg.dpdk.ref.app
2022-08-30 11:17 ` Zhang, Qi Z
2022-08-31 22:42 ` Mah, Yock Gen
2022-09-01 8:22 ` David Marchand
2022-09-02 7:01 ` David Marchand
2022-08-31 22:51 ` [PATCH v2] " iotg.dpdk.ref.app
2022-09-02 0:18 ` [PATCH v3] " yock.gen.mah
2022-09-04 1:55 ` Zhang, Qi Z
2022-10-11 11:04 ` [PATCH v2] " Kevin Traynor
2022-10-12 7:45 ` Mah, Yock Gen
2022-10-12 8:39 ` Kevin Traynor
2022-10-18 12:54 ` Kevin Traynor
2022-10-18 22:45 ` Mah, Yock Gen
2022-10-19 8:34 ` Kevin Traynor [this message]
2022-12-20 15:47 ` Kevin Traynor
2022-12-21 3:01 ` Mah, Yock Gen
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