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Date:   Tue, 4 Jun 2019 09:31:40 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Akinobu Mita <akinobu.mita@gmail.com>
Cc:     Christoph Hellwig <hch@lst.de>, linux-nvme@lists.infradead.org,
        linux-pm@vger.kernel.org, Zhang Rui <rui.zhang@intel.com>,
        Eduardo Valentin <edubezval@gmail.com>,
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        Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>,
        Sagi Grimberg <sagi@grimberg.me>,
        Minwoo Im <minwoo.im.dev@gmail.com>,
        Kenneth Heitke <kenneth.heitke@intel.com>,
        Chaitanya Kulkarni <Chaitanya.Kulkarni@wdc.com>
Subject: Re: [PATCH v3 2/3] nvme: add thermal zone devices
Message-ID: <20190604073140.GH15680@lst.de>
References: <1558888143-5121-1-git-send-email-akinobu.mita@gmail.com> <1558888143-5121-3-git-send-email-akinobu.mita@gmail.com> <20190601090238.GD6453@lst.de> <CAC5umyiBmD6-3BNLfG7sNOe9jde8Ct16a9N_Ao3T_1_G1K_DDA@mail.gmail.com>
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On Sun, Jun 02, 2019 at 10:19:08PM +0900, Akinobu Mita wrote:
> As long as the user space thermal governor is used, there is nothing more
> than that from a functional perspective.  And I suppose that this is used
> with user_space governor (i.e. there is still some work to be able to bind
> actual thermal cooling device).
> 
> The main purpose of this is to turn on a fan when overheated without
> polling the device that could prevent the lower power state transitions.
> But as you noted, we could do that with the existing AEN notifications
> through uevent.
> 
> So frankly speaking, the benefit of this is providing generic thermal sysfs
> interface and the tools like tmon (linux/tools/thermal/tmon) can show the
> nvme temperatures.

I'm just a little worried about bloating the nvme driver with features
that look kinda nifty but don't buy us much.  I'd rather keep at least
the core and PCIe drivers as minimal.  Now the thermal device support
is pretty small and except for the smart uevents I can't find anything
actually bad, but I'm not exactly excited either.