From: Samuel Holland <samuel@sholland.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
Thomas Gleixner <tglx@linutronix.de>,
Rob Herring <robh+dt@kernel.org>,
Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
Jernej Skrabec <jernej.skrabec@siol.net>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>
Cc: devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer
Date: Tue, 23 Mar 2021 22:51:00 -0500 [thread overview]
Message-ID: <64f6d712-11fe-4626-aa24-8e31c21a8ad4@sholland.org> (raw)
In-Reply-To: <7bb14a82-5dc9-cefe-4b58-1d2c83974965@linaro.org>
On 3/22/21 9:18 AM, Daniel Lezcano wrote:
> On 22/03/2021 05:47, Samuel Holland wrote:
>> In preparation for adding CPU idle states, hook up the sun4i timer.
>> Having a non-c3stop clockevent source available is necessary for all
>> CPUs to simultaneously enter a local-timer-stop idle state.
>
> Why simultaneously ?
Because the CPU providing (the hrtimer providing) the broadcast timer
cannot enter an idle state which would stop that timer. So in my case,
with 4 CPUs, I was seeing at most 3 CPUs enter idle at any given time.
This prevented any cluster-level idle states from doing anything. After
applying this series, I was able to observe the whole cluster powering
down when appropriate.
Regards,
Samuel
>> Changes from v1:
>> - Removed H616 changes (depends on an unmerged patch set)
>> - Reworded the patch 4-5 commit messages for clarity
>> - Added Acked-by tags
>>
>> Samuel Holland (5):
>> dt-bindings: timer: Simplify conditional expressions
>> dt-bindings: timer: Add compatibles for sun50i timers
>> arm64: dts: allwinner: a64: Sort watchdog node
>> arm64: dts: allwinner: Add sun4i MMIO timer nodes
>> arm64: sunxi: Build the sun4i timer driver
>>
>> .../timer/allwinner,sun4i-a10-timer.yaml | 42 +++++++++----------
>> arch/arm64/Kconfig.platforms | 1 +
>> arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi | 25 +++++++----
>> arch/arm64/boot/dts/allwinner/sun50i-h6.dtsi | 9 ++++
>> 4 files changed, 46 insertions(+), 31 deletions(-)
>>
>
>
next prev parent reply other threads:[~2021-03-24 3:51 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-22 4:47 [PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer Samuel Holland
2021-03-22 4:47 ` [PATCH v2 1/5] dt-bindings: timer: Simplify conditional expressions Samuel Holland
2021-03-27 16:44 ` Rob Herring
2021-03-22 4:47 ` [PATCH v2 2/5] dt-bindings: timer: Add compatibles for sun50i timers Samuel Holland
2021-03-27 16:46 ` Rob Herring
2021-03-22 4:47 ` [PATCH v2 3/5] arm64: dts: allwinner: a64: Sort watchdog node Samuel Holland
2021-03-22 4:47 ` [PATCH v2 4/5] arm64: dts: allwinner: Add sun4i MMIO timer nodes Samuel Holland
2021-03-22 4:47 ` [PATCH v2 5/5] arm64: sunxi: Build the sun4i timer driver Samuel Holland
2021-03-22 14:18 ` [PATCH v2 0/5] arm64: sunxi: Enable the sun4i timer Daniel Lezcano
2021-03-24 3:51 ` Samuel Holland [this message]
2021-03-24 9:33 ` Daniel Lezcano
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