Re: [PATCH net-next 5/6] net: stmmac: move PHY handling out of __stmmac_open()/release()

[Alexander Stein <alexander.stein@ew.tq-group.com>]

Am Mittwoch, 15. April 2026, 14:59:32 CEST schrieb Russell King (Oracle):
> On Wed, Apr 15, 2026 at 08:08:40AM +0200, Alexander Stein wrote:
> > Hi,
> > 
> > Am Dienstag, 23. September 2025, 13:26:19 CEST schrieb Russell King (Oracle):
> > > Move the PHY attachment/detachment from the network driver out of
> > > __stmmac_open() and __stmmac_release() into stmmac_open() and
> > > stmmac_release() where these actions will only happen when the
> > > interface is administratively brought up or down. It does not make
> > > sense to detach and re-attach the PHY during a change of MTU.
> > 
> > Sorry for coming up now. But I recently noticed this commit breaks changing
> > the MTU on i.MX8MP. Once I simply change the MTU I run into some DMA error:
> > $ ip link set dev end1 mtu 1400
> > imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-0
> > imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-1
> > imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-2
> > imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-3
> > imx-dwmac 30bf0000.ethernet end1: Register MEM_TYPE_PAGE_POOL RxQ-4
> > imx-dwmac 30bf0000.ethernet end1: Link is Down
> > imx-dwmac 30bf0000.ethernet end1: Failed to reset the dma
> > imx-dwmac 30bf0000.ethernet end1: stmmac_hw_setup: DMA engine initialization failed
> 
> This basically means that a clock is missing. Please provide more
> information:
> 
> - what kernel version are you using?

Currently I am using v6.18.22.
$ ethtool -i end1
driver: st_gmac
version: 6.18.22
firmware-version: 
expansion-rom-version: 
bus-info: 30bf0000.ethernet
supports-statistics: yes
supports-test: no
supports-eeprom-access: no
supports-register-dump: yes
supports-priv-flags: no

> - has EEE been negotiated?

No. It is marked as not supported

$ ethtool --show-eee end1
EEE settings for end1:
        EEE status: not supported

> - does the problem persist when EEE is disabled?

As EEE is not supported the problem occurs even with EEE disabled.

> - which PHY is attached to stmmac?

It is a TI DP83867.

imx-dwmac 30bf0000.ethernet eth1: PHY [stmmac-1:03] driver [TI DP83867] (irq=136)

> - which PHY interface mode is being used to connect the PHY to stmmac?

For this interface
> phy-mode = "rgmii-id";
is set.

In case it is helpful. My platform is arch/arm64/boot/dts/freescale/imx8mp-tqma8mpql-mba8mpxl.dts
Thanks for assisting. If there a further questions, don't hesitate to ask.

Thanks and best regards
Alexander
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