quoted

quoted

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- System suspend/resume
1. Enable USB wakeup
for i in $(find /sys -name wakeup | grep usb);do echo enabled  >
$i;echo "echo enabled > $i";done; 2. Let the system enter suspend
using below command echo mem > /sys/power/state 3. And see if there
is a wakeup block system entering suspend, and check if USB HSIC
works ok after system resume

System suspend/resume seems to work fine. After resume the ethernet
controller works.

root@imxceet-solo-s-43:~# echo mem > /sys/power/state
PM: suspend entry (deep)
PM: Syncing filesystems ... done.
Freezing user space processes ... (elapsed 0.001 seconds) done.
OOM killer disabled.
Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
smsc95xx 3-1:1.0 eth1: entering SUSPEND2 mode
PM: suspend devices took 0.050 seconds Disabling non-boot CPUs ...
usb 3-1: reset high-speed USB device number 2 using ci_hdrc
PM: resume devices took 0.590 seconds OOM killer enabled.
Restarting tasks ... done.
PM: suspend exit
smsc95xx 3-1:1.0 eth1: link up, 100Mbps, full-duplex, lpa 0x4DE1 fec
2188000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx

quoted

- Runtime suspend
1. Enable auto suspend for all USB devices, and check if USBOH3
clock is closed, make sure do not plug any ethernet cable on the
RJ45 port.

/* Enable auto suspend */
for i in $(find /sys -name control | grep usb);do echo auto  >
$i;echo "echo auto > $i";done;

This doesn't work. When the port is suspended it gets into a loop of
suspending/resuming endlessly. If i put two logs in
ci_hdrc_imx_runtime_suspend() and ci_hdrc_imx_runtime_resume(), I get
this:

[...]
ci_hdrc_imx_runtime_resume:603
ci_hdrc_imx_runtime_suspend:574
ci_hdrc_imx_runtime_resume:603
ci_hdrc_imx_runtime_suspend:574
ci_hdrc_imx_runtime_resume:603
ci_hdrc_imx_runtime_suspend:574
ci_hdrc_imx_runtime_resume:603
ci_hdrc_imx_runtime_suspend:574
[...]

Ok, forget about the loop, this was caused by one of the other ports,
that had issues with overcurrent detection.

But still it doesn't work for the HSIC port.

The HSIC device is stuck in status "suspending" (note: "suspending"
and not "suspended"):

~# cat /sys/bus/usb/devices/usb1/power/runtime_status
suspended
~# cat /sys/bus/usb/devices/usb2/power/runtime_status
suspended
~# cat /sys/bus/usb/devices/usb3/power/runtime_status
active
~# cat /sys/bus/usb/devices/usb3/3-1/power/runtime_status
suspending

It seems like this is a problem with the smsc95xx driver. I fixed this and now the
device is suspending properly, when the network interface is down and resumes
when it comes up.

I also checked the USBOH3 clock and its properly switched on and off.

What didn't work is auto suspend and resume on ethernet link down/up, but this
seems to be a restriction of the smsc95xx/usbnet driver.

So all in all this looks good to me. Please let me know if you need any more
information or tests.

Thanks, Frieder, no more tests are needed.
You could send me your dts changes as patches, I will append it at my v2 patch series.

Peter