[PATCH v2] net: macb: add TX stall timeout callback to recover from lost TSTART write

[Théo Lebrun]

Hello Andrea,

On Tue Jun 16, 2026 at 3:23 PM CEST, Andrea della Porta wrote:
> From: Lukasz Raczylo <lukasz at raczylo.com>
>
> The MACB found in the Raspberry Pi RP1 suffers from sporadic stalls on
> the TX queue.
> While the exact root cause is not yet fully understood, it is likely
> related to a hardware issue where a TSTART write to the NCR register
> is missed, preventing the transmission from being kicked off.
>
> Implement a timeout callback to handle TX queue stalls, triggering the
> existing restart mechanism to recover.
>
> Link: https://lore.kernel.org/all/20260514215459.36109-1-lukasz@raczylo.com/
> Fixes: dc110d1b23564 ("net: cadence: macb: Add support for Raspberry Pi RP1 ethernet controller")
> Signed-off-by: Lukasz Raczylo <lukasz at raczylo.com>
> Co-developed-by: Steffen Jaeckel <sjaeckel at suse.de>
> Signed-off-by: Steffen Jaeckel <sjaeckel at suse.de>
> Co-developed-by: Andrea della Porta <andrea.porta at suse.com>
> Signed-off-by: Andrea della Porta <andrea.porta at suse.com>

Thanks for this V2.

Reviewed-by: Théo Lebrun <theo.lebrun at bootlin.com>

Any news from the Raspberry Pi community about this bug investigation?

Thanks,

--
Théo Lebrun, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com