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

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

On Mon, Oct 27, 2025 at 09:45:54AM +0000, Russell King (Oracle) wrote:
> On Mon, Oct 27, 2025 at 11:33:46AM +0200, Laurent Pinchart wrote:
> > On Mon, Oct 27, 2025 at 09:07:32AM +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.
> > > 
> > > As this is the second problem that has been reported recently, please
> > > bisect the conversion of stmmac to phylink managed EEE support and see
> > > whether there is anything in that which is causing this.
> > 
> > Emanuele Ghidoli has bisected this to commit 2c81f3357136 ("net: stmmac:
> > convert to phylink PCS support"), as reported in [1]. I can test that
> > commit and the commit just before tonight.
> > 
> > [1] https://lore.kernel.org/all/341f56de-9dde-4c44-9542-b523e1917dcb@gmail.com/
> 
> As you will notice in that thread, I have responded to it last week, so
> I am well aware of it. I am also well aware of the claims Emanuele made
> in his commit description are demonstrably false.
> 
> That's not to say the commit isn't a problem, but the explanation of
> why it's a problem doesn't make sense right now, and thus what needs to
> be done to fix it is unknown.
> 
> I don't think going around disabling EEE on individual platforms is the
> right approach.

I fully agree with you, seeing how eee-broken-1000t spread on many
i.MX8MP DT sources raised a red cargo-cult flag. I didn't have the
knowledge to properly diagnose and fix this myself, hence this patch,
hoping someone more knowledgeable than me could help. Based on the
replies received so far, it seems I was right to be hopeful :-)

I'll perform more tests tonight, printing the interrupt status values as
you requested in a separate e-mail.

-- 
Regards,

Laurent Pinchart