Hi Ulf,
On Tue, Oct 25, 2016 at 11:31 PM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
> On 25 October 2016 at 15:59, Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
>> On Mon, Oct 17, 2016 at 8:17 PM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
>>> When resuming a device in __pm_runtime_set_status(), the prerequisite is
>>> that its parent must already be active, else an error code is returned and
>>> the device's status remains suspended.
>>>
>>> When suspending a device there is no similar constraints being validated.
>>> Let's change this to make the behaviour consistent, by not allowing to
>>> suspend a device with an active child, unless it has been explicitly set to
>>> ignore its children.
>>>
>>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>>
>> This is now commit 8b1107b85efd78c in pm/linux-next.
>>
>> This breaks resume from s2ram on r8a73a4/ape6evm and sh73a0/kzm9g, where the
>> smsc911x Ethernet is connected to an external bus, whose clock is controlled
>> through Runtime PM and the simple-pm-bus driver.
>>
>> Reverting this commit fixes the issue.
>
> Geert, thanks again for testing and reporting. I believe this problem
> is directly related to what you reported for another patch [1] as
> well.
Indeed. At first I thought that patch got applied, but I couldn't find it ;-)
> Can you please try out this rather trivial patch to the Ethernet
> driver (smsc911x), to see if that solves the problem(s).
Thanks, it does!
Difference between before and after is:
PM: Suspending system (mem)
cpg_div6_clock_disable: sdhi1ck
cpg_div6_clock_disable: sdhi0ck
-PM: suspend of devices complete after 22.932 msecs
-PM: late suspend of devices complete after 7.311 msecs
+PM: suspend of devices complete after 23.131 msecs
+PM: late suspend of devices complete after 7.300 msecs
cpg_div6_clock_disable: mmc0
cpg_div6_clock_disable: zb
-simple-pm-bus fec10000.bus: runtime PM trying to suspend device but
active child
rmobile_pd_power_down: a3sp
-PM: noirq suspend of devices complete after 26.937 msecs
+PM: noirq suspend of devices complete after 18.467 msecs
Disabling non-boot CPUs ...
-Suspended for 2.579 seconds
+Suspended for 2.949 seconds
rmobile_pd_power_up: a3sp
+cpg_div6_clock_enable: zb
cpg_div6_clock_enable: sdhi0ck
cpg_div6_clock_enable: sdhi1ck
cpg_div6_clock_enable: mmc0
-PM: noirq resume of devices complete after 128.014 msecs
-PM: early resume of devices complete after 6.121 msecs
-Unhandled fault: imprecise external abort (0x1406) at 0x00000000
The zb clock is enabled again.
BTW, shouldn't "runtime PM trying to suspend device but active child"
become a WARN()? If this happens, something is really wrong, and
the device will be left in half-suspended state (clock disabled).
> From: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Date: Tue, 25 Oct 2016 23:11:51 +0200
> Subject: [PATCH] net: smsc911x: Synchronize the runtime PM status during
> system suspend
>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Tested-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
