From: m.szyprowski@samsung.com (Marek Szyprowski)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/5] clk: add support for runtime pm
Date: Thu, 15 Sep 2016 10:32:04 +0200 [thread overview]
Message-ID: <648b0ce0-dcc5-d32d-5c4e-b7e0c0f10d4c@samsung.com> (raw)
In-Reply-To: <20160914213903.GG7243@codeaurora.org>
Hi Stephen,
On 2016-09-14 23:39, Stephen Boyd wrote:
> On 09/13, Marek Szyprowski wrote:
>> On 2016-09-13 00:31, Stephen Boyd wrote:
>>> Great! So you have runtime PM callbacks that are calling
>>> clk_prepare/unprepare?
>> Well, not really. clock controller's runtime pm functions must not call
>> clk_prepare/unprepare yet.
>>
>> I didn't get your question. I thought that you are asking if my change
>> won't introduce any deadlock related to prepare and dev->pm locks. My
>> runtime pm functions doesn't do any call to clk_prepare/unprepare.
>> Although global clock prepare lock is re-entrant from the same process, it
>> would cause deadlock if called from runtime pm functions, because runtime
>> pm functions might be called from the worker running on the different
>> cpu/process.
> I mean non-clk controller driver based runtime PM callbacks that
> call clk_prepare/unprepare in them. For example, some i2c or spi
> device driver that has clk operations in the runtime PM
> callbacks. That would allow lockdep to see any potential deadlock
> because of aliasing lock classes for the device power lock and
> the global prepare lock.
This works perfectly fine. Runtime pm callbacks are called with power lock
released, so there is no deadlock possible related to dev->power.lock.
See __rpm_callback() function in drivers/base/power/runtime.c
Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland
next prev parent reply other threads:[~2016-09-15 8:32 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-01 13:45 [PATCH 0/5] Add runtime PM support for clocks (on Exynos SoC example) Marek Szyprowski
2016-09-01 13:45 ` [PATCH 1/5] clk: add support for runtime pm Marek Szyprowski
2016-09-01 15:10 ` kbuild test robot
2016-09-01 15:10 ` [PATCH] clk: fix boolreturn.cocci warnings kbuild test robot
2016-09-08 0:19 ` [PATCH 1/5] clk: add support for runtime pm Stephen Boyd
[not found] ` <CGME20160912101857eucas1p29b2bbd5ac0eda92284091ad1b86decc4@eucas1p2.samsung.com>
2016-09-12 10:18 ` Marek Szyprowski
2016-09-12 22:31 ` Stephen Boyd
2016-09-13 9:07 ` Marek Szyprowski
2016-09-14 21:39 ` Stephen Boyd
2016-09-15 8:32 ` Marek Szyprowski [this message]
2016-09-13 7:24 ` Ulf Hansson
2016-09-13 8:49 ` Ulf Hansson
2016-09-13 13:13 ` Marek Szyprowski
2016-09-13 15:03 ` Ulf Hansson
2016-09-14 10:11 ` Marek Szyprowski
2016-09-01 13:45 ` [PATCH 2/5] clock: samsung: " Marek Szyprowski
2016-09-01 13:45 ` [PATCH 3/5] clocks: exynos4x12: add runtime pm support for ISP clocks Marek Szyprowski
2016-09-01 21:49 ` kbuild test robot
2016-09-01 13:45 ` [PATCH 4/5] ARM: dts: exynos: add support for ISP power domain to exynos4x12 clocks device Marek Szyprowski
2016-09-08 0:22 ` Stephen Boyd
[not found] ` <CGME20160912102332eucas1p145e79669788329b44343da62dcbe50ca@eucas1p1.samsung.com>
2016-09-12 10:23 ` Marek Szyprowski
2016-09-12 22:28 ` Stephen Boyd
2016-09-15 12:06 ` Marek Szyprowski
2016-09-15 14:13 ` Ulf Hansson
2016-09-01 13:45 ` [PATCH 5/5] clocks: exynos5433: add runtime pm support Marek Szyprowski
2016-09-01 16:55 ` Bartlomiej Zolnierkiewicz
2016-09-01 23:00 ` kbuild test robot
2016-09-02 19:05 ` kbuild test robot
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