linux-kernel - Re: [PATCH v8 3/5] amba: Don't unprepare the clocks if device driver wants IRQ safe runtime PM

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Date:	Tue, 04 Nov 2014 08:59:29 +0100
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Russell King - ARM Linux <linux@....linux.org.uk>
Cc:	Alan Stern <stern@...land.harvard.edu>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>,
	Len Brown <len.brown@...el.com>, Pavel Machek <pavel@....cz>,
	Jonathan Corbet <corbet@....net>,
	Dan Williams <dan.j.williams@...el.com>,
	Vinod Koul <vinod.koul@...el.com>,
	Ulf Hansson <ulf.hansson@...aro.org>, linux-pm@...r.kernel.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	dmaengine@...r.kernel.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: [PATCH v8 3/5] amba: Don't unprepare the clocks if device driver
 wants IRQ safe runtime PM

On pon, 2014-11-03 at 15:44 +0000, Russell King - ARM Linux wrote:
> On Mon, Nov 03, 2014 at 10:41:02AM -0500, Alan Stern wrote:
> > Bear in mind, however, that once the irq_safe flag has been set, the 
> > runtime PM core offers no way to turn it off again.
> 
> Ah, I thought it did permit it to change both ways.  In that case, we
> don't need to validate that it doesn't change state on each call, and
> we can just get away with checking its value.

It cannot be unset but still it could be *set* during runtime (not only
in probe). However that shouldn't happen between suspend-resume calls,
so the solution of undoing suspend's work seems fine.

I'll send a new patch doing this way. Without the wrapper.

Best regards,
Krzysztof



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