From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH] nvme/pci: Use host managed power state for suspend
Date: Tue, 14 May 2019 08:11:41 +0200 [thread overview]
Message-ID: <20190514061141.GA7059@lst.de> (raw)
In-Reply-To: <df020e90e8b54244b37910a2a7965671@AUSX13MPC105.AMER.DELL.COM>
On Mon, May 13, 2019@06:01:39PM +0000, Mario.Limonciello@dell.com wrote:
> When using HMB the SSD will be writing to some memory mapped region.
> Writing to
> that region would use DMA to access host memory, no?
Memory mapped region? It will use the devices DMA engine to write
host memory, which we explicitly allowed it.
> If the DMA controller is not functional writing to that region won't work properly as
> it can't access that memory.
The DMA controller is in the device. External DMA controllers are only
used on very low-end periphals, usually cheap IP blocks like SPI
controllers or similar.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Mario.Limonciello@dell.com
Cc: hch@lst.de, kbusch@kernel.org, keith.busch@intel.com,
sagi@grimberg.me, linux-nvme@lists.infradead.org,
rafael@kernel.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org, kai.heng.feng@canonical.com
Subject: Re: [PATCH] nvme/pci: Use host managed power state for suspend
Date: Tue, 14 May 2019 08:11:41 +0200 [thread overview]
Message-ID: <20190514061141.GA7059@lst.de> (raw)
In-Reply-To: <df020e90e8b54244b37910a2a7965671@AUSX13MPC105.AMER.DELL.COM>
On Mon, May 13, 2019 at 06:01:39PM +0000, Mario.Limonciello@dell.com wrote:
> When using HMB the SSD will be writing to some memory mapped region.
> Writing to
> that region would use DMA to access host memory, no?
Memory mapped region? It will use the devices DMA engine to write
host memory, which we explicitly allowed it.
> If the DMA controller is not functional writing to that region won't work properly as
> it can't access that memory.
The DMA controller is in the device. External DMA controllers are only
used on very low-end periphals, usually cheap IP blocks like SPI
controllers or similar.
next prev parent reply other threads:[~2019-05-14 6:11 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-10 21:29 [PATCH] nvme/pci: Use host managed power state for suspend Keith Busch
2019-05-10 21:29 ` Keith Busch
2019-05-11 0:52 ` Mario.Limonciello
2019-05-11 0:52 ` Mario.Limonciello
2019-05-11 0:52 ` Mario.Limonciello
2019-05-13 14:24 ` Mario.Limonciello
2019-05-13 14:24 ` Mario.Limonciello
2019-05-13 14:24 ` Mario.Limonciello
2019-05-13 14:37 ` Christoph Hellwig
2019-05-13 14:37 ` Christoph Hellwig
2019-05-13 14:43 ` Mario.Limonciello
2019-05-13 14:43 ` Mario.Limonciello
2019-05-13 14:43 ` Mario.Limonciello
2019-05-13 14:54 ` Christoph Hellwig
2019-05-13 14:54 ` Christoph Hellwig
2019-05-13 14:55 ` Keith Busch
2019-05-13 14:55 ` Keith Busch
2019-05-13 15:05 ` Mario.Limonciello
2019-05-13 15:05 ` Mario.Limonciello
2019-05-13 15:05 ` Mario.Limonciello
2019-05-13 15:04 ` Keith Busch
2019-05-13 15:04 ` Keith Busch
2019-05-14 8:04 ` Rafael J. Wysocki
2019-05-14 8:04 ` Rafael J. Wysocki
2019-05-14 22:16 ` Keith Busch
2019-05-14 22:16 ` Keith Busch
2019-05-15 9:00 ` Rafael J. Wysocki
2019-05-15 9:00 ` Rafael J. Wysocki
2019-05-13 14:37 ` Keith Busch
2019-05-13 14:37 ` Keith Busch
2019-05-13 14:54 ` Mario.Limonciello
2019-05-13 14:54 ` Mario.Limonciello
2019-05-13 14:54 ` Mario.Limonciello
2019-05-13 14:57 ` Christoph Hellwig
2019-05-13 14:57 ` Christoph Hellwig
2019-05-13 15:16 ` Keith Busch
2019-05-13 15:16 ` Keith Busch
2019-05-13 17:16 ` Kai-Heng Feng
2019-05-13 17:16 ` Kai-Heng Feng
2019-05-13 18:16 ` Keith Busch
2019-05-13 18:16 ` Keith Busch
2019-05-13 18:01 ` Mario.Limonciello
2019-05-13 18:01 ` Mario.Limonciello
2019-05-13 18:01 ` Mario.Limonciello
2019-05-14 6:11 ` Christoph Hellwig [this message]
2019-05-14 6:11 ` Christoph Hellwig
2019-05-11 1:33 ` Edmund Nadolski
2019-05-11 1:33 ` Edmund Nadolski
2019-05-11 7:22 ` Christoph Hellwig
2019-05-11 7:22 ` Christoph Hellwig
2019-05-12 14:34 ` Sagi Grimberg
2019-05-12 14:34 ` Sagi Grimberg
2019-05-13 13:36 ` Keith Busch
2019-05-13 13:36 ` Keith Busch
2019-05-12 6:06 ` Chaitanya Kulkarni
2019-05-12 6:06 ` Chaitanya Kulkarni
2019-05-12 14:30 ` Minwoo Im
2019-05-12 14:30 ` Minwoo Im
2019-05-12 15:20 ` Chaitanya Kulkarni
2019-05-12 15:20 ` Chaitanya Kulkarni
2019-05-13 13:47 ` Keith Busch
2019-05-13 13:47 ` Keith Busch
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