Re: [PATCH] arm64: dts: imx8mp-debix-model-a: Disable EEE for 1000T

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

(CC'ing Catalin)

On Tue, Oct 28, 2025 at 12:57:55AM +0000, Russell King (Oracle) wrote:
> On Tue, Oct 28, 2025 at 01:46:48AM +0200, Laurent Pinchart wrote:
> > On Mon, Oct 27, 2025 at 03:13:51PM +0000, Russell King (Oracle) wrote:
> > > On Sun, Oct 26, 2025 at 02:29:04PM +0200, Laurent Pinchart wrote:
> > > > Energy Efficient Ethernet (EEE) is broken at least for 1000T on the EQOS
> > > > (DWMAC) interface. When connected to an EEE-enabled peer, the ethernet
> > > > devices produces an interrupts storm. Disable EEE support to fix it.
> > > 
> > > We've finally got to the bottom of what's going on here. Please try
> > > this patch (it's building locally, but will take some time because
> > > I'd wound the tree back to 6.13 and 6.14, so it's going to be a full
> > > rebuild.) Thus, there may be compile bugs remaining.
> > 
> > I've applied it on top of 
> > 
> > I've started with a branch based on v6.18-rc3 plus "[PATCH net-next 0/5]
> > net: stmmac: more cleanups" ([1]) and "[PATCH net-next v2 0/6] net: add
> > phylink managed WoL and convert stmmac" ([2]) to make the patch apply
> > cleanly.
> > 
> > [1] https://lore.kernel.org/all/aO_HIwT_YvxkDS8D@shell.armlinux.org.uk/
> > [2] https://lore.kernel.org/all/aPnyW54J80h9DmhB@shell.armlinux.org.uk/
> > 
> > The base branch exhibits the interrupt storm issue. The patch
> > unfortunately doesn't fix it.
> 
> So it's highly unlikely that your problem is the same as Emanuele's.
> 
> Do you know when the interrupt storm behaviour started? If not, I'd
> suggest testing 6.13 and 6.14 as a starting point to see whether
> the phylink-managed EEE conversion is involved.

I can't test it right now (no access to hardware during daytime for this
week), but if I recall correctly my colleague Stefan Klug bisected the
issue to

commit dda1bc1d8ad13672c2728eedee0dd02d27a5314a
Author: Catalin Popescu <catalin.popescu@leica-geosystems.com>
Date:   Mon Oct 7 15:44:24 2024 +0200

    arm64: dts: imx8mp: add cpuidle state "cpu-pd-wait"

    So far, only WFI is supported on i.MX8mp platform. Add support for
    deeper cpuidle state "cpu-pd-wait" that would allow for better power
    usage during runtime. This is a port from NXP downstream kernel.

    Signed-off-by: Catalin Popescu <catalin.popescu@leica-geosystems.com>
    Signed-off-by: Shawn Guo <shawnguo@kernel.org>

I didn't notice it at the time because my board was connected to a
switch that didn't support EEE.

-- 
Regards,

Laurent Pinchart