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Date: Mon, 15 Sep 2014 09:07:43 +0200 From: Krzysztof Kozlowski <k.kozlowski@...sung.com> To: Russell King - ARM Linux <linux@....linux.org.uk> Cc: Dan Williams <dan.j.williams@...el.com>, Vinod Koul <vinod.koul@...el.com>, linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org, Ulf Hansson <ulf.hansson@...aro.org>, Grant Likely <grant.likely@...aro.org>, Lars-Peter Clausen <lars@...afoo.de>, Michal Simek <michal.simek@...inx.com>, Kyungmin Park <kyungmin.park@...sung.com>, Marek Szyprowski <m.szyprowski@...sung.com>, Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com> Subject: Re: [RFC PATCH v2 1/2] amba: Allow AMBA drivers to use their own runtime PM On piÄ…, 2014-09-12 at 16:13 +0100, Russell King - ARM Linux wrote: > On Fri, Sep 12, 2014 at 04:56:18PM +0200, 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()). If such driver > > implements its own runtime PM functions then assume it will handle the > > runtime PM completely and it will replace our clock handling. > > > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@...sung.com> > > Actually, I'd rather just revert 5303c0f46c8708fff4148ebcc491f78710356952 > which is clearly the wrong thing to do when we have non-IRQ safe runtime > PM. > > What we /could/ do instead is to check whether irq_safe is set after > probe, record that, and then select whether to use the prepare/unprepare > methods based on that. (Drivers should never dynamically change this.) I'll try this approach. Thank you for feedback, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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