> -----Original Message-----
> From: Russell King <linux@xxxxxxxxxxxxxxx>
> Sent: 06 July 2025 11:11
> To: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Cc: Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>; Andrew Lunn
> <andrew+netdev@xxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric Dumazet <edumazet@xxxxxxxxxx>;
> Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo Abeni <pabeni@xxxxxxxxxx>; Maxime Coquelin
> <mcoquelin.stm32@xxxxxxxxx>; Alexandre Torgue <alexandre.torgue@xxxxxxxxxxx>; netdev@xxxxxxxxxxxxxxx;
> linux-renesas-soc@xxxxxxxxxxxxxxx; linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Geert Uytterhoeven
> <geert+renesas@xxxxxxxxx>; biju.das.au <biju.das.au@xxxxxxxxx>
> Subject: Re: [PATCH net-next] net: stmmac: dwmac-renesas-gbeth: Add PM suspend/resume callbacks
>
> On Sun, Jul 06, 2025 at 09:55:28AM +0000, Biju Das wrote:
> > Just adding some logs:
> > Currently PHY resume is called twice
> > [ 35.754933] kszphy_resume+0x3c/0xf0
> > [ 35.754940] phy_resume+0x3c/0x74
> > [ 35.754949] phylink_prepare_resume+0x58/0xa0
> > [ 35.754957] stmmac_resume+0x90/0x2a0
> > [ 35.771296] stmmac_pltfr_resume+0x3c/0x4c
> >
> > and
> >
> > [ 35.771258] kszphy_resume+0x3c/0xf0
> > [ 35.771263] __phy_resume+0x28/0x54
> > [ 35.771270] phy_start+0x7c/0xb4
> > [ 35.771275] phylink_start+0xb8/0x210
> > [ 35.771282] phylink_resume+0x7c/0xc4
> > [ 35.771288] stmmac_resume+0x1ec/0x2a0
> > [ 35.771296] stmmac_pltfr_resume+0x3c/0x4c
>
> This shouldn't be a problem. Phylib will do this, and PHY drivers are expected to cope.
>
> For example, on non-MAC managed PM PHYs, mdio_bus_phy_resume() will call phy_init_hw() followed by
> phy_resume(). If a MAC subsequently is brought up, phy_start() will be called, which will also call
> __phy_resume().
>
> If this is upsetting the KSZ PHY, then the KSZ PHY driver needs fixing.
By reconfiguring rgmii_delay during resume also fixes the issue.
Not sure, PHY device is expected to configure the delay during every resume?
if (phy_interface_is_rgmii(phydev)) {
ret = ksz9131_config_rgmii_delay(phydev);
if (ret < 0)
return ret;
}
Cheers,
Biju
