[RFC,net-next,0/3] net: stmmac: approach 2 to solve EEE LPI reset issues

Message

Russell King (Oracle) March 4, 2025, 10:53 a.m. UTC

Hi,

This is a second approach to solving the STMMAC reset issues caused by
the lack of receive clock from the PHY where the media is in low power
mode with a PHY that supports receive clock-stop.

The first approach centred around only addressing the issue in the
resume path, but it seems to also happen when the platform glue module
is removed and re-inserted (Jon - can you check whether that's also
the case for you please?)

As this is more targetted, I've dropped the patches from this series
which move the call to phylink_resume(), so the link may still come
up too early on resume - but that's something I also intend to fix.

This is experimental - so I value test reports for this change.

As mentioned recently, the reset timeout will only occur if the PHY
receive clock is actually stopped at the moment that stmmac_reset()
is called and remains stopped for the duration of the timeout.
Network activity can wake up the link, causing the PHY to restart
its receive clock and allow reset to complete. So, careful testing
with and without these patches is necessary.

 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c |  3 ++
 drivers/net/phy/phylink.c                         | 54 ++++++++++++++++++++++-
 include/linux/phylink.h                           |  3 ++
 3 files changed, 59 insertions(+), 1 deletion(-)