On Thursday, December 12, 2024 6:59:20 AM CET Christoph Hellwig wrote: > On Mon, Dec 09, 2024 at 08:08:21PM +0530, Manivannan Sadhasivam wrote: > > > > > > The istory here is the the NVMe internal power states are significantly > > > better for the SSDs. It avoid shutting down the SSD frequently, which > > > creates a lot of extra erase cycles and reduces life time. It also > > > prevents the SSD from performing maintainance operations while the host > > > system is idle, which is the perfect time for them. But the idea of > > > putting all periphals into D3 is gaining a lot of ground because it > > > makes the platform vendors life a lot simpler at the cost of others. > > > > No, I disagree with the last comment. When the system goes to low power mode > > (like S2R/hibernate), it *does* makes a lot of sense to put the devices into > > D3Cold to save power. > > Yes. That's what the pm_suspend_via_firmware call in nvme_suspend is > supposed to catch. pm_suspend_via_firmware() is to distinguish different flavors of system suspend. For runtime-suspend, there are different callbacks, but it doesn't look like they are used by NVMe. At least nvme_dev_pm_ops doesn't set them.
