Re: [PATCH] riscv: dts: spacemit: k3-pico-itx: Fix non-functional ethernet TX timing

[Andrew Rembrandt <kernel@rembrandt.dev>]

Hi E, Yixun,

On Fri, Jul 10, 2026 at 07:34:34 am E Shattow wrote:
> On the topic of this ethernet TX timing thread I don't know what
> this does? Is there a test situation I may try to know if it is doing
> anything? Thanks very much, -E
Apologies for the slow reply -- I've been swamped the past month.

Thank you for taking the time to test this; your results are what
prompted me to go back and re-test properly, and it turns out my
original premise was wrong.

The non-functional TX I originally saw was not fixed by this delay
property at all. An unrelated commit that landed between v7.1-rc1 and
v7.1-rc7 is what actually fixed the dead TX on my board. While
developing this patch I'd inadvertently picked up that change, and I
wrongly concluded the tx-internal-delay-ps addition was what got traffic
flowing.

To confirm, I re-ran a series of iperf3 tests without the delay patch
and saw no transmission problem whatsoever -- a full 1Gb/s in both
directions with no errors. So this matches exactly what you and perhaps
Yixun also observed: on a current base the property makes no measurable
difference, because the TX path already works without it.

Given that, the patch isn't the fix as described in the changelog, and
the property has no functional effect on this board.

Yixun -- since you've already applied it, could you drop it from your
tree? A revert is fine too if it's landed somewhere non-rewindable, but
I don't think it should go upstream as-is: the "Fixes:" tag and the "no
ethernet traffic passes" rationale are both wrong. Sorry for the hassle,
and thanks for queuing it in good faith.


Sorry again for the noise, and thanks E for the careful testing that
caught this.