Re: [PATCH] arm64: dts: rockchip: Add idle-states to device tree for rk3399

From: Tao Huang <huangtao@rock-chips.com>
To: Heiko Stuebner <heiko@sntech.de>, Caesar Wang <wxt@rock-chips.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree@vger.kernel.org,
	Brian Norris <briannorris@chromium.org>,
	Xing Zheng <zhengxing@rock-chips.com>,
	Masahiro Yamada <yamada.masahiro@socionext.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	dbasehore@chromium.org, Will Deacon <will.deacon@arm.com>,
	dianders@chromium.org, Rob Herring <robh+dt@kernel.org>,
	linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
	tony.xie@rock-chips.com, David Wu <david.wu@rock-chips.com>,
	cf@rock-chips.com, Jianqun Xu <jay.xu@rock-chips.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] arm64: dts: rockchip: Add idle-states to device tree for rk3399
Date: Mon, 13 Aug 2018 00:24:45 +0800	[thread overview]
Message-ID: <ae312dc3-f640-ecf3-049a-c8576bb83330@rock-chips.com> (raw)
In-Reply-To: <5620784.b19SH5PkdR@phil>

Hi Heiko:

On 2018年08月10日 04:09, Heiko Stuebner wrote:
> Am Mittwoch, 6. Juli 2016, 10:20:54 CEST schrieb Caesar Wang:
>
>>  arch/arm64/boot/dts/rockchip/rk3399.dtsi | 18 ++++++++++++++++++
>>  1 file changed, 18 insertions(+)
>>
>> diff --git a/arch/arm64/boot/dts/rockchip/rk3399.dtsi b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
>> index a6dd623..12ce265 100644
>> --- a/arch/arm64/boot/dts/rockchip/rk3399.dtsi
>> +++ b/arch/arm64/boot/dts/rockchip/rk3399.dtsi
>> @@ -101,6 +101,18 @@
>>  			};
>>  		};
>>  
>> +		idle-states {
>> +			entry-method = "psci";
>> +			cpu_sleep: cpu-sleep-0 {
>> +				compatible = "arm,idle-state";
>> +				local-timer-stop;
>> +				arm,psci-suspend-param = <0x0010000>;
>> +				entry-latency-us = <350>;
>> +				exit-latency-us = <600>;
>> +				min-residency-us = <1150>;
> Looking at the chromeos kernel, there are some more patches adapting
> this idle-state to use different timings.
Yes, we have another values. So the values of this patch are wrong.
>
> There also was a cluster-idle state added for a while but that seems to
> cause audio issues according to the CrOS history.

DMA or Audio driver should add PM_QOS_CPU_DMA_LATENCY or other methods to avoid the effects of idle.
Idle itself is good.

Thanks!