[PATCH net-next v2 0/2] declance: Improve DMA error reporting

[PATCH net-next v2 0/2] declance: Improve DMA error reporting

[Maciej W. Rozycki]

Hi,

 D'oh, this v2 fixes a silly thinko in the commit description of 2/2.

 Inspired by a recent discussion[1] I have come up with this pair of 
small improvements to DMA error reporting with declance.  Please apply.

References:

[1] Sebastian Andrzej Siewior, "declance: Remove IRQF_ONESHOT",
    <https://lore.kernel.org/r/20260127135334.qUEaYP9G@linutronix.de/>

  Maciej

[PATCH net-next v2 1/2] declance: Rate-limit DMA errors

[Maciej W. Rozycki]

Prevent the system from becoming unusable due to a flood of DMA error
messages.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
No change from v1.
---
 drivers/net/ethernet/amd/declance.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

linux-declance-ratelimit.diff
Index: linux-macro/drivers/net/ethernet/amd/declance.c
===================================================================
--- linux-macro.orig/drivers/net/ethernet/amd/declance.c
+++ linux-macro/drivers/net/ethernet/amd/declance.c
@@ -727,7 +727,7 @@ static irqreturn_t lance_dma_merr_int(in
 {
 	struct net_device *dev = dev_id;
 
-	printk(KERN_ERR "%s: DMA error\n", dev->name);
+	pr_err_ratelimited("%s: DMA error\n", dev->name);
 	return IRQ_HANDLED;
 }
 

[PATCH net-next v2 2/2] declance: Include the offending address with DMA errors

[Maciej W. Rozycki]

The address latched in the I/O ASIC LANCE DMA Pointer Register uses the 
TURBOchannel bus address encoding and therefore bits 33:29 of location 
referred occupy bits 4:0, bits 28:2 are left-shifted by 3, and bits 1:0 
are hardwired to zero.  In reality no TURBOchannel system exceeds 1GiB 
of RAM though, so the address reported will always fit in 8 hex digits.

Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
---
Changes from v1:

- s/16/8/ in the change description for the printed address width.
---
 drivers/net/ethernet/amd/declance.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

linux-declance-dma-merr-addr.diff
Index: linux-macro/drivers/net/ethernet/amd/declance.c
===================================================================
--- linux-macro.orig/drivers/net/ethernet/amd/declance.c
+++ linux-macro/drivers/net/ethernet/amd/declance.c
@@ -726,8 +726,10 @@ static void lance_tx(struct net_device *
 static irqreturn_t lance_dma_merr_int(int irq, void *dev_id)
 {
 	struct net_device *dev = dev_id;
+	u64 ldp = ioasic_read(IO_REG_LANCE_DMA_P);
 
-	pr_err_ratelimited("%s: DMA error\n", dev->name);
+	pr_err_ratelimited("%s: DMA error at %#010llx\n", dev->name,
+			   (ldp & 0x1f) << 29 | (ldp & 0xffffffe0) >> 3);
 	return IRQ_HANDLED;
 }
 

Re: [PATCH net-next v2 0/2] declance: Improve DMA error reporting

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Sun, 29 Mar 2026 19:07:18 +0100 (BST) you wrote:
> Hi,
> 
>  D'oh, this v2 fixes a silly thinko in the commit description of 2/2.
> 
>  Inspired by a recent discussion[1] I have come up with this pair of
> small improvements to DMA error reporting with declance.  Please apply.
> 
> [...]

Here is the summary with links:
  - [net-next,v2,1/2] declance: Rate-limit DMA errors
    https://git.kernel.org/netdev/net-next/c/ee769323b1bf
  - [net-next,v2,2/2] declance: Include the offending address with DMA errors
    https://git.kernel.org/netdev/net-next/c/aae5efaeb8aa

You are awesome, thank you!
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