netdev - Re: [PATCH net-next] r8169: set EEE speed down ratio to 1

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Message-ID: <f2cb249e-0e73-4c4f-b2ca-d3b3c71ece2d@gmail.com>
Date: Fri, 5 Sep 2025 21:57:18 +0200
From: Heiner Kallweit <hkallweit1@...il.com>
To: Hau <hau@...ltek.com>, nic_swsd <nic_swsd@...ltek.com>,
 "andrew+netdev@...n.ch" <andrew+netdev@...n.ch>,
 "davem@...emloft.net" <davem@...emloft.net>,
 "edumazet@...gle.com" <edumazet@...gle.com>,
 "kuba@...nel.org" <kuba@...nel.org>, "pabeni@...hat.com" <pabeni@...hat.com>
Cc: "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
 "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH net-next] r8169: set EEE speed down ratio to 1

On 9/5/2025 3:43 PM, Hau wrote:
>>
>> On 9/4/2025 4:11 AM, ChunHao Lin wrote:
>>> EEE speed down ratio (mac ocp 0xe056[7:4]) is used to control EEE
>>> speed down rate. The larger this value is, the more power can save.
>>> But it actually save less power then expected, but will impact
>>> compatibility. So set it to 1 (mac ocp 0xe056[7:4] = 0) to improve
>> compatibility.
>>>
>> Hi Hau,
>>
>> what kind of speed is this referring to? Some clock, or link speed, or ..?
>> Is EEE speed down a Realtek-specific feature?
>>
>> Are there known issues with the values used currently? Depending on the
>> answer we might consider this a fix.
>>
> It means clock (MAC MCU) speed down. It is not from spec, so it is kind of Realtek specific feature.
> It may cause packet drop or interrupt loss (different hardware may have different issue).
> 
Thanks, Hau!

>>
>>> Signed-off-by: ChunHao Lin <hau@...ltek.com>
>>> ---
>>>  drivers/net/ethernet/realtek/r8169_main.c | 6 +++---
>>>  1 file changed, 3 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/net/ethernet/realtek/r8169_main.c
>>> b/drivers/net/ethernet/realtek/r8169_main.c
>>> index 9c601f271c02..e5427dfce268 100644
>>> --- a/drivers/net/ethernet/realtek/r8169_main.c
>>> +++ b/drivers/net/ethernet/realtek/r8169_main.c
>>> @@ -3409,7 +3409,7 @@ static void rtl_hw_start_8168h_1(struct
>> rtl8169_private *tp)
>>>               r8168_mac_ocp_modify(tp, 0xd412, 0x0fff, sw_cnt_1ms_ini);
>>>       }
>>>
>>> -     r8168_mac_ocp_modify(tp, 0xe056, 0x00f0, 0x0070);
>>> +     r8168_mac_ocp_modify(tp, 0xe056, 0x00f0, 0x0000);
>>>       r8168_mac_ocp_modify(tp, 0xe052, 0x6000, 0x8008);
>>>       r8168_mac_ocp_modify(tp, 0xe0d6, 0x01ff, 0x017f);
>>>       r8168_mac_ocp_modify(tp, 0xd420, 0x0fff, 0x047f); @@ -3514,7
>>> +3514,7 @@ static void rtl_hw_start_8117(struct rtl8169_private *tp)
>>>               r8168_mac_ocp_modify(tp, 0xd412, 0x0fff, sw_cnt_1ms_ini);
>>>       }
>>>
>>> -     r8168_mac_ocp_modify(tp, 0xe056, 0x00f0, 0x0070);
>>> +     r8168_mac_ocp_modify(tp, 0xe056, 0x00f0, 0x0000);
>>>       r8168_mac_ocp_write(tp, 0xea80, 0x0003);
>>>       r8168_mac_ocp_modify(tp, 0xe052, 0x0000, 0x0009);
>>>       r8168_mac_ocp_modify(tp, 0xd420, 0x0fff, 0x047f); @@ -3715,7
>>> +3715,7 @@ static void rtl_hw_start_8125_common(struct rtl8169_private
>> *tp)
>>>       r8168_mac_ocp_modify(tp, 0xc0b4, 0x0000, 0x000c);
>>>       r8168_mac_ocp_modify(tp, 0xeb6a, 0x00ff, 0x0033);
>>>       r8168_mac_ocp_modify(tp, 0xeb50, 0x03e0, 0x0040);
>>> -     r8168_mac_ocp_modify(tp, 0xe056, 0x00f0, 0x0030);
>>> +     r8168_mac_ocp_modify(tp, 0xe056, 0x00f0, 0x0000);
>>>       r8168_mac_ocp_modify(tp, 0xe040, 0x1000, 0x0000);
>>>       r8168_mac_ocp_modify(tp, 0xea1c, 0x0003, 0x0001);
>>>       if (tp->mac_version == RTL_GIGA_MAC_VER_70 ||
>