ACK/cmt / APPLIED[D]: [PATCH 0/1][SRU][B][C][D][OEM-B]PC SN720 NVMe WDC 256GB consumes more power in S2Idle than during long idle
seth.forshee at canonical.com
Wed Dec 5 13:57:17 UTC 2018
On Thu, Nov 29, 2018 at 03:44:23PM +0800, AceLan Kao wrote:
> To avoid conflicts, this patch assumes below commits have been applied
> on top of master-next branch on Bionic, Cosmic, and Disco kernel,
> since both patches modify the same files on the same position for the
> same issue.
> BugLink: https://bugs.launchpad.net/bugs/1805775
> On new systems that facilitate s2idle, we observed the power consumption
> raises higher than long idle does during s2idle with Western Digital PC
> SN720 NVMe SSD SDAPNTW-256G.
> Short idle: 5.3
> Long idle: 3.0
> S2I: 5.07
> Windows doesn't put nvme to D3 in modern standby, and uses its own APST
> feature to do the power management. To leverage its APST feature during
> s2idle, we can't disable nvme device while suspending, too.
> So, here is what we did on the driver, 1. prevent nvme from entering D3,
> 2. prevent nvme from being disabled when suspending.
> Verified on the WD NVMe, it fixes the power consumption issue with no
> regression. And the power consumption decreases to 1.66W during s2idle.
> [Regression Potential]
> Low, the patches only applied to specific nvme module, and from our test,
> the system is still stable.
Scope limited to a single device, positive testing. Note though that the
patches should be prefixed with "UBUNTU: SAUCE:" and not just "SAUCE:".
Acked-by: Seth Forshee <seth.forshee at canonical.com>
Is this patch going upstream?
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