Messages in this thread | | | Date | Tue, 4 Nov 2014 21:18:34 +0100 | From | Pavel Machek <> | Subject | Re: [PATCH v9 2/4] amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM |
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On Tue 2014-11-04 13:52:48, Krzysztof Kozlowski wrote: > The AMBA bus driver defines runtime Power Management functions which > disable and unprepare AMBA bus clock. This is problematic for runtime PM > because unpreparing a clock might sleep so it is not interrupt safe. > > However some drivers may want to implement runtime PM functions in > interrupt-safe way (see pm_runtime_irq_safe()). In such case the AMBA > bus driver should only disable/enable the clock in runtime suspend and > resume callbacks.
> /* > * Hooks to provide runtime PM of the pclk (bus clock). It is safe to > * enable/disable the bus clock at runtime PM suspend/resume as this > @@ -95,8 +102,14 @@ static int amba_pm_runtime_suspend(struct device *dev) > struct amba_device *pcdev = to_amba_device(dev); > int ret = pm_generic_runtime_suspend(dev); > > - if (ret == 0 && dev->driver) > - clk_disable_unprepare(pcdev->pclk); > + if (ret == 0 && dev->driver) { > + pcdev->irq_safe = get_pm_runtime_irq_safe(dev); > + > + if (pcdev->irq_safe) > + clk_disable(pcdev->pclk); > + else > + clk_disable_unprepare(pcdev->pclk); > + }
So you can handle the case of !pcdev->irq_safe. What is the penalty for always assuming !pcdev->irq_safe? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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