[PATCH net v4 03/15] net: phylink: allow stopping a suspended instance
flat view
COOLING13d
From: James Hilliard <hidden>
Date: 2026-09-26 15:49:26
Also in:
bpf, linux-sunxi, linux-tegra, lkml
Subsystem:
ethernet phy library, networking drivers, sff/sfp/sfp+ module support, the rest · Maintainers:
Andrew Lunn, Heiner Kallweit, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Russell King, Linus Torvalds
If a network driver's system resume fails before phylink_resume(), the
network device can remain administratively up with phylink suspended.
Closing the interface then needs to terminate that suspended instance.
Calling phylink_resume() merely to make phylink_stop() work is not a
safe substitute: resume reconfigures the MAC and restarts link
resolution, although the driver has not successfully restored the MAC.
This is a missing suspend-to-stop transition, independent of the reason
hardware restoration failed. No MAC recovery policy belongs in phylink;
the driver still decides whether to retry resume or wait for an ordinary
administrative down/up cycle.
Without MAC Wake-on-LAN, phylink_suspend() has already called
phylink_stop(). Do not repeat PHY, SFP and PCS shutdown. However,
phylink_prepare_resume() may have powered that stopped PHY back up to
provide the receive clock for MAC reset. Suspend it again if WoL
permits, without repeating phy_stop() on a PHY which is already halted.
With MAC Wake-on-LAN, suspend deliberately defers mac_link_down() and
sets PHYLINK_DISABLE_MAC_WOL. Finish that deferred link-down, drain
resolution work and clear the WoL disable bit while retaining
PHYLINK_DISABLE_STOPPED. Otherwise a subsequent start cannot resolve the
link.
Also undo PHY speed control performed by phylink_suspend(). As Andrew
Lunn pointed out, phylink_start() does not restore the advertised speeds
that phylink_resume() normally restores. Track suspend-owned speed
control and restore the saved advertisement from either resume or
suspended stop, including when PHY shutdown has already completed.
An explicit driver speed-down request, such as stmmac's close-time power
saving, must remain in effect until its matching speed-up. Restore any
suspend-owned reduction before applying that request, so it cannot save
the reduced advertisement over the original one. The following stop must
not undo the driver's new reduction.
Document that a suspended instance can be stopped directly. This neither
resumes the PHY nor reconfigures or brings up the MAC.
Fixes: f97493657c63 ("net: phylink: add suspend/resume support")
Signed-off-by: James Hilliard <redacted>
---
drivers/net/phy/phylink.c | 51 ++++++++++++++++++++++++++++++++++++++++++++---
1 file changed, 48 insertions(+), 3 deletions(-)
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 1bbcf46c8356..b7d30ca34031 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c@@ -78,6 +78,7 @@ struct phylink { bool link_failed; bool suspend_link_up; + bool suspend_speed_down; bool force_major_config; bool major_config_failed; bool mac_supports_eee_ops;
@@ -2498,6 +2499,14 @@ void phylink_start(struct phylink *pl) } EXPORT_SYMBOL_GPL(phylink_start); +static void phylink_restore_suspend_speed(struct phylink *pl) +{ + if (pl->suspend_speed_down) { + phylink_speed_up(pl); + pl->suspend_speed_down = false; + } +} + /** * phylink_stop() - stop a phylink instance * @pl: a pointer to a &struct phylink returned from phylink_create()
@@ -2509,11 +2518,30 @@ EXPORT_SYMBOL_GPL(phylink_start); * * This will synchronously bring down the link if the link is not already * down (in other words, it will trigger a mac_link_down() method call.) + * A suspended instance may be stopped without first calling phylink_resume(). + * In particular, closing a device after a failed resume must not restart the + * link or reconfigure the MAC just to finish shutting it down. + * Any PHY advertisement reduced by phylink_suspend() is restored as part + * of this transition. + * If phylink_prepare_resume() powered up an already stopped PHY, suspend + * it again when Wake-on-LAN permits. */ void phylink_stop(struct phylink *pl) { ASSERT_RTNL(); + /* Also undo PHY speed control when terminating a suspended instance. */ + phylink_restore_suspend_speed(pl); + + if (test_bit(PHYLINK_DISABLE_STOPPED, &pl->phylink_disable_state)) { + /* A failed MAC resume may have called phylink_prepare_resume() + * and powered the stopped PHY back up to supply its RX clock. + */ + if (pl->phydev) + phy_suspend(pl->phydev); + return; + } + if (pl->sfp_bus) sfp_upstream_stop(pl->sfp_bus); if (pl->phydev)
@@ -2526,6 +2554,16 @@ void phylink_stop(struct phylink *pl) phylink_run_resolve_and_disable(pl, PHYLINK_DISABLE_STOPPED); + if (test_bit(PHYLINK_DISABLE_MAC_WOL, &pl->phylink_disable_state)) { + /* Finish the link-down deferred by MAC WoL, without restarting. */ + flush_work(&pl->resolve); + mutex_lock(&pl->state_mutex); + if (pl->suspend_link_up) + phylink_link_down(pl); + __clear_bit(PHYLINK_DISABLE_MAC_WOL, &pl->phylink_disable_state); + mutex_unlock(&pl->state_mutex); + } + pl->pcs_state = PCS_STATE_DOWN; phylink_pcs_disable(pl->pcs);
@@ -2657,8 +2695,10 @@ void phylink_suspend(struct phylink *pl, bool mac_wol) phylink_stop(pl); } - if (phylink_phy_pm_speed_ctrl(pl)) + if (phylink_phy_pm_speed_ctrl(pl)) { phylink_speed_down(pl, false); + pl->suspend_speed_down = true; + } } EXPORT_SYMBOL_GPL(phylink_suspend);
@@ -2698,8 +2738,7 @@ void phylink_resume(struct phylink *pl) { ASSERT_RTNL(); - if (phylink_phy_pm_speed_ctrl(pl)) - phylink_speed_up(pl); + phylink_restore_suspend_speed(pl); if (test_bit(PHYLINK_DISABLE_MAC_WOL, &pl->phylink_disable_state)) { /* Wake-on-Lan enabled, MAC handling */
@@ -3616,6 +3655,12 @@ int phylink_speed_down(struct phylink *pl, bool sync) ASSERT_RTNL(); + /* An explicit request takes over from suspend-time speed control. + * Restore the original advertisement before saving it again, so a + * repeated speed-down cannot replace it with the reduced advertisement. + */ + phylink_restore_suspend_speed(pl); + if (!pl->sfp_bus && pl->phydev) ret = phy_speed_down(pl->phydev, sync);
--
2.53.0