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Message-Id: <235CF4F8-19BF-4B00-8C92-E59CB2D476A7@canonical.com>
Date: Thu, 20 Feb 2020 16:08:06 +0800
From: Kai-Heng Feng <kai.heng.feng@...onical.com>
To: Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>
Cc: Linux PM <linux-pm@...r.kernel.org>, linux-ide@...r.kernel.org,
open list <linux-kernel@...r.kernel.org>,
Kent Lin <kent.lin@...onical.com>
Subject: Re: Hard Disk consumes lots of power in s2idle
Hi Srinivas,
> On Feb 20, 2020, at 02:36, Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com> wrote:
>
> Hi Kai,
>
> On Wed, 2020-02-19 at 22:22 +0800, Kai-Heng Feng wrote:
>> Hi Srinivas,
>>
>> Your previous work to support DEVSLP works well on SATA SSDs, so I am
>> asking you the issue I am facing:
>> Once a laptop has a HDD installed, the power consumption during
>> S2Idle increases ~0.4W, which is quite a lot.
>> However, HDDs don't seem to support DEVSLP, so I wonder if you know
>> to do proper power management for HDDs?
> What is the default here
> cat /sys/power/mem_sleep
> s2idle or deep?
It defaults to s2idle.
>
> Please follow debug steps here:
> https://01.org/blogs/qwang59/2018/how-achieve-s0ix-states-linux
>
> We need to check whether you get any PC10 residency or not.
Yes it reaches PC10. It doesn't reach SLP_S0 though.
The real number on S2Idle power consumption:
No HDD: ~1.4W
One HDD: ~1.8W
If the SoC doesn't hit PC10 the number should be significantly higher.
That's why I think the issue is the power management on HDD itself.
Kai-Heng
>
> Thanks,
> Srinivas
>
>
>>
>> Kai-Heng
>
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