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Date:   Mon, 5 Nov 2018 23:10:11 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     AceLan Kao <acelan.kao@canonical.com>
Cc:     Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-pci@vger.kernel.org
Subject: Re: [PATCH 1/2] pci: prevent sk hynix nvme from entering D3
Message-ID: <20181106071011.GA23935@infradead.org>
References: <20181106020402.21120-1-acelan.kao@canonical.com>
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On Tue, Nov 06, 2018 at 10:04:01AM +0800, AceLan Kao wrote:
> It leads to the power consumption raises to 2.2W during s2idle, while
> it consumes less than 1W during long idle if put SK hynix nvme to D3
> and then enter s2idle.
> >From SK hynix FE, MS Windows doesn't put nvme to D3, and uses its own
> APST feature to do the power management.
> To leverage its APST feature during s2idle, we can't disable nvme
> device while suspending, too.
> 
> BTW, prevent it from entering D3 will increase the power consumtion around
> 0.13W ~ 0.15W during short/long idle, and the power consumption during
> s2idle becomes 0.77W.

Please get this fixed in firmware.  And yes, depending on which Windows
driver you use Windows might be doing very agressive runtime D3, which
is parted of Windows modern standby, so it'll trip up there eventually 
as well.