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

["Russell King (Oracle)" <linux@armlinux.org.uk>]

On Sat, Nov 22, 2025 at 04:22:46PM +0900, Laurent Pinchart wrote:
> Hello Wei,
> 
> On Tue, Nov 18, 2025 at 01:50:55AM +0000, Wei Fang wrote:
> > Sorry, I only have a little experience with DWMac, add Clark to help look
> > at this issue.
> 
> Thank you.
> 
> I think we're getting close to having a good understanding of the
> problem. I've debugged it as far as I could based on the information
> available publicly. Let's try to get to the bottom of this issue, it
> impacts quite a lot of people and it would be very nice to fix it
> properly in mainline.
> 
> The short summary is that I'm experiencing an interrupt storm on IRQ 135
> when EEE is enabled with the EQOS interface.
> 
> My current theory is that
> 
> - The lpi_intr_o signal of the EQOS is OR'ed into IRQ 135.
> - The issue is triggerted by the PHY exiting LPI mode
> - When it exits LPI mode, the PHY restarts generating the RX clock
>   (clk_rx_i).
> - The MAC detects exit from LPI, and asserts lpi_intr_o.
> - Before the CPU has time to process the interrupt, the PHY enters LPI
>   mode again, and stops generating the RX clock.
> - The CPU processes the interrupt and reads the GMAC4_LPI_CTRL_STATUS
>   registers. This does not clear lpi_intr_o as there's no clk_rx_i.

Please try setting STMMAC_FLAG_RX_CLK_RUNS_IN_LPI in dwmac-imx.c and
see whether that changes the behaviour.

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