Since the introduction of mac_managed_pm in the FEC driver there were some
discrepancies regarding power management of the PHY.
This failed on our board that has a permanently powered Microchip LAN8700R
attached to the FEC. Although the root cause of the failure can be traced
back to f166f890c8f0 ("net: ethernet: fec: Replace interrupt driven MDIO
with polled IO") and probably even before that, we only started noticing
the problem going from 5.10 to 6.1.
Since 557d5dc83f68 ("net: fec: use mac-managed PHY PM") is actually a fix
to most of the power management sequencing problems that came with power
managing the MDIO bus which for the FEC meant adding a race with FEC
resume (and phy_start() if netif was running) and PHY resume.
That it worked before for us was probably just luck...
Thanks to Wei's response to my report at [1] I was able to pick up his
patch and start honing in on the remaining missing details.
[1]: https://lore.kernel.org/netdev/1f45bdbe-eab1-4e59-8f24-add177590d27@actia.se/
v4:
- Adjustments to commit message in patch 1
- Drop patch 2 after discussion in v3.
v3: https://lore.kernel.org/netdev/20240306133734.4144808-1-john.ernberg@actia.se/
- Implement feedback from Wei Fang for patch 2
- Fixes tag in patch 2 dropped, should it be delayed for net-next now?
v2: https://lore.kernel.org/netdev/20240229105256.2903095-1-john.ernberg@actia.se/
- Completely different approach that should be much more correct
(Wei Fang, Jakub Kicinski)
- Re-target to net tree, because I have fixes tags now
v1: https://lore.kernel.org/netdev/20240212105010.2258421-1-john.ernberg@actia.se/
Wei Fang (1):
net: fec: Set mac_managed_pm during probe
drivers/net/ethernet/freescale/fec_main.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--
2.44.0
discrepancies regarding power management of the PHY.
This failed on our board that has a permanently powered Microchip LAN8700R
attached to the FEC. Although the root cause of the failure can be traced
back to f166f890c8f0 ("net: ethernet: fec: Replace interrupt driven MDIO
with polled IO") and probably even before that, we only started noticing
the problem going from 5.10 to 6.1.
Since 557d5dc83f68 ("net: fec: use mac-managed PHY PM") is actually a fix
to most of the power management sequencing problems that came with power
managing the MDIO bus which for the FEC meant adding a race with FEC
resume (and phy_start() if netif was running) and PHY resume.
That it worked before for us was probably just luck...
Thanks to Wei's response to my report at [1] I was able to pick up his
patch and start honing in on the remaining missing details.
[1]: https://lore.kernel.org/netdev/1f45bdbe-eab1-4e59-8f24-add177590d27@actia.se/
v4:
- Adjustments to commit message in patch 1
- Drop patch 2 after discussion in v3.
v3: https://lore.kernel.org/netdev/20240306133734.4144808-1-john.ernberg@actia.se/
- Implement feedback from Wei Fang for patch 2
- Fixes tag in patch 2 dropped, should it be delayed for net-next now?
v2: https://lore.kernel.org/netdev/20240229105256.2903095-1-john.ernberg@actia.se/
- Completely different approach that should be much more correct
(Wei Fang, Jakub Kicinski)
- Re-target to net tree, because I have fixes tags now
v1: https://lore.kernel.org/netdev/20240212105010.2258421-1-john.ernberg@actia.se/
Wei Fang (1):
net: fec: Set mac_managed_pm during probe
drivers/net/ethernet/freescale/fec_main.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
--
2.44.0