Santosh Shilimkar <santosh.shilim...@ti.com> writes: [...]
>>> 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) >> > One way to deal with this is to have clk_unprepare()/clk_prepare() > called from dev_pm_domain ops before calling pm_clk_[suspend/resume]() if we > can't have that as part of runtime code. That doesn't solve the irq_safe problem that Stephen pointed out without being very careful. Basically, if you have _any_ potentially sleeping calls in this path, you can never allow devices to use pm_runtime_irq_safe(). Also, I don't like having the clk_enable in the PM core but the clk_prepare in the platform-specific pm_domain. That seems prone for platforms to get wrong. I'll need to think about this a little more before having any idea what to do here. Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
