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Date:   Wed, 18 Jan 2023 06:24:50 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Janne Grunau <j@jannau.net>
Cc:     Hector Martin <marcan@marcan.st>, Sven Peter <sven@svenpeter.dev>,
        Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>,
        Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Eric Curtin <ecurtin@redhat.com>, asahi@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] nvme-apple: Reset controller during shutdown
Message-ID: <20230118052450.GA24742@lst.de>
References: <20230114-apple-nvme-suspend-fixes-v6.2-v2-0-9157bf633dba@jannau.net> <20230114-apple-nvme-suspend-fixes-v6.2-v2-1-9157bf633dba@jannau.net>
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On Tue, Jan 17, 2023 at 07:25:00PM +0100, Janne Grunau wrote:
> +		/*
> +		 * Always reset the NVMe controller on shutdown. The reset is
> +		 * required to shutdown the co-processor cleanly.
> +		 */

Hmm.  This comment doesn't seem to match the discussion we had last
week.  Which would be:

		/*
		 * NVMe requires a reset before setting up a controller to
		 * ensure it is in a clean state.  For NVMe PCIe this is
		 * done in the setup path to be able to deal with controllers
		 * in any kind of state.  For for Apple devices, the firmware
		 * will not be available at that time and the reset will
		 * time out.  Thus reset after shutting the NVMe controller
		 * down and before shutting the firmware down.
		 */