* bigeasy@xxxxxxxxxxxxx <bigeasy@xxxxxxxxxxxxx> [160824 08:24]: > On 2016-08-24 15:16:08 [+0000], Shevchenko, Andriy wrote: > > On Wed, 2016-08-24 at 17:03 +0200, bigeasy@xxxxxxxxxxxxx wrote: > > > On 2016-08-24 14:56:12 [+0000], Shevchenko, Andriy wrote: > > > > > > Today I discovered that runtime PM rather broken in 8250 _by > > > > design_. > > > > > > > > It > > > > definitely requires irq_safe flag to be set in runtime PM. But that > > > > flag > > > > demolishes an effort since it keeps parent (and thus all other > > > > devices > > > > which parent needs to be on) always on. > > > > ^^^^^ (1) > > > > > > > > > > The question is is somebody is going to fix this and when? > > > > > > Why is it broken? > > > > I meant that without irq_safe flag set there are too many places where > > "sleep while in atomic" happens. On the other hand the irq_safe flag > > prevents parent to go to suspend. > > This must be new then. I don't remember _any_ "sleeping while atomic" > warnings back then. Maybe Tony knows something. Maybe it does not occur > on TI's PM code. I would have to reanimate my beagle bone to check that. PM runtime with UARTs has been working for me just fine for quite some time now. I'm mostly using omap-serial still and have not checked with 8250-omap recently. But yeah I agree that PM runtime should be improved and simplified for 8250. We should not use irq_safe at all and instead fix up things so runtime_resume wakes up things with pm_runtime_get without get_sync. This adds latency only to the first wake-up event which can already take a long time at least on omaps as things are getting powered back on. No idea how to implement that though for cases when there's no dedicated wakeirq.. Maybe change the irq to a threaded irq for the duration of idle for 8250 irq? Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
