On 7/17/26 5:40 PM, Andrew Lunn wrote:

quoted

I tested the changes as you suggested and it seems DMA_CHAN_INTR_ENA_RPS in DMA_CHAN_INTR_ABNORMAL_4_10 broke it.
With this change on master suspend is working:

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
index 43b036d4e95b..e907142c9ee2 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_dma.h

@@ -121,7 +121,6 @@ static inline u32 dma_chanx_base_addr(const struct dwmac4_addrs *addrs,
                                         DMA_CHAN_INTR_ENA_TIE)
 
 #define DMA_CHAN_INTR_ABNORMAL_4_10    (DMA_CHAN_INTR_ENA_AIE_4_10 | \
-                                        DMA_CHAN_INTR_ENA_RPS | \
                                         DMA_CHAN_INTR_ENA_RBU | \
                                         DMA_CHAN_INTR_ENA_FBE)
 /* DMA default interrupt mask for 4.10a */

OK, that narrows it down a bit.

I made the guess it is an interrupt storm during suspend, because
interrupts are not disabled. DMA_CHAN_INTR_ABNORMAL_4_10 is written to
hardware in dwmac410_dma_init_channel(). However, i don't see anywhere
these interrupts are clear? struct stmmac_dma_ops has an init_chan
operation, but there is no opposite operation to reset a channel?
There is however disable_dma_irq. Maybe DMA_CHAN_INTR_ENA_RPS can be
cleared there?

But i'm also having trouble finding where dwmac4_disable_dma_irq() is
actually called. It is called from stmmac_disable_rx_queue() and
stmmac_disable_tx_queue() but they only seem to be used in the XDP
code.

Are the DMAs being stopped during suspend? I don't know this driver
well enough to answer that.

Can you scatter some printk() around and see what actually happens on
suspend. See if you can find somewhere to disable that one interrupt?

	 Andrew

It seems your assumptions are correct. If i do

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c
index a0249715fafa..487efc746b20 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_lib.c

@@ -129,6 +129,8 @@ void dwmac4_disable_dma_irq(struct stmmac_priv *priv, void __iomem *ioaddr,
        const struct dwmac4_addrs *dwmac4_addrs = priv->plat->dwmac4_addrs;
        u32 value = readl(ioaddr + DMA_CHAN_INTR_ENA(dwmac4_addrs, chan));
 
+       value &= ~DMA_CHAN_INTR_ENA_RPS;
+
        if (rx)
                value &= ~DMA_CHAN_INTR_ENA_RIE;
        if (tx)

I can suspend and resume!
Could it be sufficient to just do this and reenable on dwmac4_enable_dma_irq?

tresonic