On 08.09.2025 13:26, Oleksij Rempel wrote:
Drop phylink_{suspend,resume}() from ax88772 PM callbacks.
MDIO bus accesses have their own runtime-PM handling and will try to wake the device if it is suspended. Such wake attempts must not happen from PM callbacks while the device PM lock is held. Since phylink {sus|re}sume may trigger MDIO, it must not be called in PM context.
No extra phylink PM handling is required for this driver:
- .ndo_open/.ndo_stop control the phylink start/stop lifecycle.
- ethtool/phylib entry points run in process context, not PM.
- phylink MAC ops program the MAC on link changes after resume.
Fixes: e0bffe3e6894 ("net: asix: ax88772: migrate to phylink") Reported-by: Hubert Wiśniewski hubert.wisniewski.25632@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Oleksij Rempel o.rempel@pengutronix.de
This patch landed in today's linux-next as commit 5537a4679403 ("net: usb: asix: ax88772: drop phylink use in PM to avoid MDIO runtime PM wakeups"). In my tests I found that it breaks operation of asix ethernet usb dongle after system suspend-resume cycle. The ethernet device is still present in the system, but it is completely dysfunctional. Here is the log:
root@target:~# time rtcwake -s10 -mmem rtcwake: wakeup from "mem" using /dev/rtc0 at Thu Sep 11 13:02:23 2025 PM: suspend entry (deep) Filesystems sync: 0.002 seconds Freezing user space processes Freezing user space processes completed (elapsed 0.003 seconds) OOM killer disabled. Freezing remaining freezable tasks Freezing remaining freezable tasks completed (elapsed 0.024 seconds) ... usb usb1: root hub lost power or was reset ... usb usb2: root hub lost power or was reset xhci-hcd xhci-hcd.7.auto: xHC error in resume, USBSTS 0x401, Reinit usb usb3: root hub lost power or was reset usb usb4: root hub lost power or was reset asix 2-1:1.0 eth0: Failed to write reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to enable software MII access asix 2-1:1.0 eth0: Failed to read reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to write reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to enable software MII access ... (the above error repeated many times) ------------[ cut here ]------------ WARNING: CPU: 0 PID: 9 at drivers/net/phy/phy.c:1346 _phy_state_machine+0x158/0x2d0 phy_check_link_status+0x0/0x140: returned: -110 Modules linked in: cmac bnep mwifiex_sdio mwifiex btmrvl_sdio btmrvl sha256 bluetooth cfg80211 s5p_mfc exynos_gsc v4l2_mem2mem videobuf2_dma_contig videobuf2_memops videobuf2_v4l2 videobuf2_common videodev ecdh_generic ecc mc s5p_cec CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.17.0-rc4-00221-g5537a4679403 #11106 PREEMPT Hardware name: Samsung Exynos (Flattened Device Tree) Workqueue: events_power_efficient phy_state_machine Call trace: unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x68/0x88 dump_stack_lvl from __warn+0x80/0x1d0 __warn from warn_slowpath_fmt+0x124/0x1bc warn_slowpath_fmt from _phy_state_machine+0x158/0x2d0 _phy_state_machine from phy_state_machine+0x24/0x44 phy_state_machine from process_one_work+0x24c/0x70c process_one_work from worker_thread+0x1b8/0x3bc worker_thread from kthread+0x13c/0x264 kthread from ret_from_fork+0x14/0x28 Exception stack(0xf0879fb0 to 0xf0879ff8) ... irq event stamp: 221553 hardirqs last enabled at (221559): [<c01bae94>] __up_console_sem+0x50/0x60 hardirqs last disabled at (221564): [<c01bae80>] __up_console_sem+0x3c/0x60 softirqs last enabled at (219346): [<c013b93c>] handle_softirqs+0x328/0x520 softirqs last disabled at (219327): [<c013bce0>] __irq_exit_rcu+0x144/0x1f0 ---[ end trace 0000000000000000 ]--- asix 2-1:1.0 eth0: Failed to write reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to enable software MII access asix 2-1:1.0 eth0: Failed to write reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to write Medium Mode mode to 0x0000: ffffff8f asix 2-1:1.0 eth0: Link is Down asix 2-1:1.0 eth0: Failed to read reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to write reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to enable software MII access asix 2-1:1.0 eth0: Failed to read reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to write reg index 0x0000: -113 asix 2-1:1.0 eth0: Failed to enable software MII access ... (the above error repeated many times) usb 2-1: reset high-speed USB device number 2 using exynos-ehci OOM killer enabled. Restarting tasks: Starting Restarting tasks: Done PM: suspend exit
real 0m14.105s user 0m0.002s sys 0m2.025s root@target:~# root@target:~# ifconfig -a eth0: flags=4099<UP,BROADCAST,MULTICAST> mtu 1500 inet 192.168.100.17 netmask 255.255.255.0 broadcast 192.168.100.255 inet6 fe80::250:b6ff:fe18:92ee prefixlen 64 scopeid 0x20<link> ether 00:50:b6:18:92:ee txqueuelen 1000 (Ethernet) RX packets 242 bytes 18250 (17.8 KiB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 258 bytes 22474 (21.9 KiB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
lo: flags=73<UP,LOOPBACK,RUNNING> mtu 65536 inet 127.0.0.1 netmask 255.0.0.0 inet6 ::1 prefixlen 128 scopeid 0x10<host> loop txqueuelen 1000 (Local Loopback) RX packets 0 bytes 0 (0.0 B) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 0 bytes 0 (0.0 B) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0
root@target:~# ping host PING host (192.168.100.1) 56(84) bytes of data. ^C --- host ping statistics --- 2 packets transmitted, 0 received, 100% packet loss, time 1053ms
Reverting $subject on top of today's linux-next restores ethernet operation after system suspend-resume cycle.
drivers/net/usb/asix_devices.c | 13 ------------- 1 file changed, 13 deletions(-)
diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c index 792ddda1ad49..1e8f7089f5e8 100644 --- a/drivers/net/usb/asix_devices.c +++ b/drivers/net/usb/asix_devices.c @@ -607,15 +607,8 @@ static const struct net_device_ops ax88772_netdev_ops = {
static void ax88772_suspend(struct usbnet *dev) {
struct asix_common_private *priv = dev->driver_priv; u16 medium;
if (netif_running(dev->net)) {
rtnl_lock();phylink_suspend(priv->phylink, false);rtnl_unlock();}
/* Stop MAC operation */ medium = asix_read_medium_status(dev, 1); medium &= ~AX_MEDIUM_RE;
@@ -644,12 +637,6 @@ static void ax88772_resume(struct usbnet *dev) for (i = 0; i < 3; i++) if (!priv->reset(dev, 1)) break;
if (netif_running(dev->net)) {
rtnl_lock();phylink_resume(priv->phylink);rtnl_unlock();} }
static int asix_resume(struct usb_interface *intf)
-- 2.47.3
Best regards