Hi Tony,

Tony Lindgren [off-list ref] writes:

Jarkko Nikula [off-list ref] reported that Beagleboard
revision c2 stopped booting. Jarkko bisected the issue down to
commit 6cfcd5563b4f ("clocksource/drivers/timer-ti-dm: Fix suspend
and resume for am3 and am4").

Let's fix the issue by tagging system timers as reserved rather than
ignoring them. And let's not probe any interconnect target module child
devices for reserved modules.

This allows PM runtime to keep track of clocks and clockdomains for
the interconnect target module, and prevent the system timer from idling
as we already have SYSC_QUIRK_NO_IDLE and SYSC_QUIRK_NO_IDLE_ON_INIT
flags set for system timers.

Fixes: 6cfcd5563b4f ("clocksource/drivers/timer-ti-dm: Fix suspend and resume for am3 and am4")
Reported-by: Jarkko Nikula <jarkko.nikula@bitmer.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>

I'm debugging why suspend/resume on AM3x and AM4x are mostly working,
but getting the warning that not all powerdomains are transitioning:

   pm33xx pm33xx: PM: Could not transition all powerdomains to target state

I bisected it down to $SUBJECT patch, and verified that reverting it
makes both on am335x-boneblack and am437x-gp-evm fully suspend, and I'm
now seeing:

   pm33xx pm33xx: PM: Successfully put all powerdomains to target state

Note that it doesn't revert cleanly due to some other changes, but this
one-liner[1] effectively reverts the behavior of $SUBJECT patch, and
also makes things work again.

I verified the revert (and hack[1]) on both v5.10 stable and mainline
v5.16 but TBH, I'm still not 100% sure what's going on so looking for
some guidance from you Tony on what the "real" fix should be.

Kevin

[1] 

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c                                                                                                            
index 54c0ee6dda30..82379ff9dce5 100644                                                                                                                               
--- a/drivers/bus/ti-sysc.c                                                                                                                                           
+++ b/drivers/bus/ti-sysc.c                                                                                                                                           

@@ -3304,7 +3304,7 @@ static int sysc_probe(struct platform_device *pdev)                                                                                             
                                                                                                                                                                      
        error = sysc_check_active_timer(ddata);                                                                                                                       
        if (error == -ENXIO)                                                                                                                                          
-               ddata->reserved = true;                                                                                                                               
+               return error;                                                                                                                                         
        else if (error)                                                                                                                                               
                return error;                                                                                                                                         
         

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