On 07/25/2017 03:56 AM, Tony Lindgren wrote:
* Tony Lindgren <t...@atomide.com> [170725 00:11]:
* Grygorii Strashko <grygorii.stras...@ti.com> [170724 15:17]:
My personal thought here is that removing of pm_runtime_set_active() will not
fix
root cause of the problem, but rather hide it :( and, probably, real fix will be
to update USB framework to ensure that all suspend devices are also PM runtime
suspend
(not sure how) or add few more pm_suspend_ignore_children() calls
(for example as I've tried to do in [2], but this was unfinished).
I've found very simple steps to reproduce suspend failure on am335x-evm (should
also
work on BBB) - do below sequence with USB device plugged:
echo platform > /sys/power/pm_test
echo 1 > /sys/power/pm_print_times
[ echo 0 > /sys/module/printk/parameters/console_suspend ]
echo mem > /sys/power/state
[ 95.499685] calling 47400000.usb+ @ 733, parent: ocp
[ 95.504818] am335x-usb-childs 47400000.usb: runtime PM trying to suspend
device but active child
[ 95.513750] am335x-usb-childs 47400000.usb: omap device suspend failure 0
Below I've attached possible patch which converts OMAP device to
use pm_runtime_force_suspend/resume().
It seems to almost work for my PM test cases.. It seems that serial console
somehow won't get restored after suspend/resume cycle on omap3 though.
The system enters off mode during suspend, and wakes up properly so I can
ssh to it after resume. But the serial console no longer works after resume.
This is with 8250-omap driver.
And FYI, on omap4 this produces a bunch of L3 irq errors on suspend.
Ok. This was a risky change even if it looks obvious :(
--
regards,
-grygorii
