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

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Message-ID: <9d8e60df8e4b464cb28c7e421b9df45a@realtek.com>
Date: Fri, 5 Sep 2025 13:43:06 +0000
From: Hau <hau@...ltek.com>
To: Heiner Kallweit <hkallweit1@...il.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 9/4/2025 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).

> 
> > 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 ||