Messages in this thread | | | From | <> | Subject | RE: [PATCH] nvme/pci: Use host managed power state for suspend | Date | Mon, 13 May 2019 14:54:49 +0000 |
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> -----Original Message----- > From: Keith Busch <kbusch@kernel.org> > Sent: Monday, May 13, 2019 9:38 AM > To: Limonciello, Mario > Cc: keith.busch@intel.com; hch@lst.de; 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 > > > [EXTERNAL EMAIL] > > On Mon, May 13, 2019 at 02:24:41PM +0000, Mario.Limonciello@dell.com wrote: > > This was not a disk with HMB, but with regard to the HMB I believe it needs to be > > removed during s0ix so that there isn't any mistake that SSD thinks it can access > HMB > > memory in s0ix. > > Is that really the case, though? Where may I find that DMA is not > allowed in this state? I just want an authoritative reference to attach > to the behavior.
The Intel DMA controller suspend callbacks in drivers/dma/idma64.c look to me to turn off the controller.
And NVME spec made it sound to me that while in a low power state it shouldn't be available if the memory isn't available.
NVME spec in 8.9:
"Host software should request that the controller release the assigned ranges prior to a shutdown event, a Runtime D3 event, or any other event that requires host software to reclaim the assigned ranges."
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