Re: [PATCH] ARM: OMAP2+: omap_device: drop broken RPM status update from suspend_noirq

[Grygorii Strashko]

On 07/25/2017 03:56 AM, Tony Lindgren wrote:
> * Tony Lindgren <tony@xxxxxxxxxxx> [170725 00:11]:
> > * Grygorii Strashko <grygorii.strashko@xxxxxx> [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