Messages in this thread | | | Date | Wed, 20 Nov 2013 22:11:48 +0200 | From | Grygorii Strashko <> | Subject | Re: [PATCH] PM / Clocks: fix pm_clk_resume/suspend if CONFIG_PM_RUNTIME is set |
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On 11/20/2013 09:53 PM, Stephen Boyd wrote: > On 11/20/13 11:06, Grygorii Strashko wrote: >> On 11/20/2013 08:42 PM, Stephen Boyd wrote: >>> On 11/20/13 05:31, Grygorii Strashko wrote: >>>> @@ -230,7 +230,7 @@ int pm_clk_suspend(struct device *dev) >>>> list_for_each_entry_reverse(ce, &psd->clock_list, node) { >>>> if (ce->status < PCE_STATUS_ERROR) { >>>> if (ce->status == PCE_STATUS_ENABLED) >>>> - clk_disable(ce->clk); >>>> + clk_disable_unprepare(ce->clk); >>>> ce->status = PCE_STATUS_ACQUIRED; >>>> } >>>> } >>>> @@ -259,7 +259,7 @@ int pm_clk_resume(struct device *dev) >>>> >>>> list_for_each_entry(ce, &psd->clock_list, node) { >>>> if (ce->status < PCE_STATUS_ERROR) { >>>> - clk_enable(ce->clk); >>>> + clk_prepare_enable(ce->clk); >>>> ce->status = PCE_STATUS_ENABLED; >>>> } >>>> } >>> This is inside a spin_lock_irqsave(). You should be getting scheduling >>> while atomic warnings with this change. Are you testing with >>> DEBUG_ATOMIC_SLEEP=y? >> Ops, thanks. No, It's not tested with DEBUG_ATOMIC_SLEEP and >> I agree with you. >> >> So, I see two option here: >> 1) split above loops on two >> 2) add calls of clk_prepare()/clk_unprepare() in pm_clk_notify() >> >> In my opinion option [2] is better. >> > > Doesn't that mean the clock will always be prepared as long as the > device is present? That doesn't sound good. I would like the clocks to > be disabled and unprepared as long as the device is suspended.
Yep (
> > What is the lock protecting? The linked list or something more? Can we > remove the locks?
Looks like it's protecting linked list pm_clock_entry'es.
> > It looks like even if you just remove the locks here, the PM core is > free to call this function with irqs disabled if pm_runtime_irq_safe() > has been called on the device. Perhaps runtime PM can only do the > clk_enable()/clk_disable() part and the clk_unprepare()/clk_prepare() > calls should happen in the system suspend callbacks?
Even don't know what to say :( On Keystone clk_unprepare()/clk_prepare() are NOPs. But clk_prepare() has to be called at least once before clk_enable() :(( So, solution with suspend/resume will not fix current problem :( unfortunately.
FYI, Now pm_clk_suspend/pm_clk_resume are called from arch/arm/mach-keystone/pm_domain.c (also similar solution is used by Davinci, but issue has not been detected because PM runtime hasn't been used by Davinci IP drivers before)
Regards, - grygorii
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