Re: [PATCH 2/5] arm64: dts: renesas: r9a09g056: Switch GBETH TX queue scheduling to WRR

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] This problem wasn't introduced by this patch, but the exact same missing `snps,tx-sched-wrr` bug remains unfixed in sibling SoCs (r9a09g047.dtsi, r9a09g077.dtsi, and r9a09g087.dtsi) that share the same GBETH hardware configuration (`renesas,rzv2h-gbeth` + `snps,dwmac-5.20`). Without specifying the WRR scheduling policy and weights, they will continue to experience Strict Priority queue starvation and netdev watchdog resets under heavy TX load.
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--- Patch [2]: [PATCH 2/5] arm64: dts: renesas: r9a09g056: Switch GBETH TX queue scheduling to WRR ---
commit 2b31533db8d80852a1d20d1d3d37f647e9c19c9d
Author: Ovidiu Panait <ovidiu.panait.rb@renesas.com>

arm64: dts: renesas: r9a09g056: Switch GBETH TX queue scheduling to WRR

The GBETH ethernet nodes don't specify a TX scheduling policy, so stmmac falls
back to Strict Priority. This starvation triggers spurious adapter resets due
to TX queue timeouts. Switch the TX scheduling policy to Weighted-Round-Robin
(WRR) so that traffic is processed across all queues, eliminating the stalls.

> diff --git a/arch/arm64/boot/dts/renesas/r9a09g056.dtsi b/arch/arm64/boot/dts/renesas/r9a09g056.dtsi
> index d6c8c39df2a4d..281500d9ee42a 100644
> --- a/arch/arm64/boot/dts/renesas/r9a09g056.dtsi
> +++ b/arch/arm64/boot/dts/renesas/r9a09g056.dtsi
> @@ -1569,23 +1569,28 @@ queue3 {
>  
>  			mtl_tx_setup0: tx-queues-config {
>  				snps,tx-queues-to-use = <4>;
> +				snps,tx-sched-wrr;

[Severity: High]
This is a pre-existing issue, but the exact same missing snps,tx-sched-wrr
configuration remains unfixed in sibling SoCs that share the same GBETH
hardware configuration.

Without specifying the WRR scheduling policy and weights, will these other
SoCs continue to experience Strict Priority queue starvation and netdev
watchdog resets under heavy TX load?

For example, in arch/arm64/boot/dts/renesas/r9a09g047.dtsi:mtl_tx_setup0:

			mtl_tx_setup0: tx-queues-config {
				snps,tx-queues-to-use = <4>;

				queue0 {
					snps,dcb-algorithm;
					snps,priority = <0x1>;
				};

The same applies to r9a09g077.dtsi and r9a09g087.dtsi.

Should a similar update be applied to these sibling SoCs?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260722085353.136986-1-ovidiu.panait.rb@renesas.com?part=2