APPLIED[Unstable]: [PATCH 0/2][SRU][B][OEM-B] Power consumption during s2idle is higher than long idle(sk hynix)

Seth Forshee seth.forshee at canonical.com
Wed Nov 7 14:25:53 UTC 2018


On Tue, Nov 06, 2018 at 06:53:10PM +0800, AceLan Kao wrote:
> BugLink: https://bugs.launchpad.net/bugs/1801875
> 
> [Impact]
> On some Dell XPS models, we observed the power consumption raises higher
> than long idle does during s2idle with sk hynix nvme.
> 
> C2:
> Short idle: 4
> Long idle: 1
> S2I: 3.7
> S5: 0.19
> 
> C3:
> Short idle: 7.2
> Long idle: 4.5
> S2I: 6.22
> S5: 0.18
> 
> C5:
> Short idle: 6.5
> Long idle: 1
> S2I: 2.88
> S5: 0.18
> 
> [Fix]
> From SK hynix FE, MS Windows doesn't put nvme to D3, 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.
> 
> [Test]
> Verified on different XPS machines with different sk hynix nvme disks,
> it fixes the power consumption issue with no regression. And the power
> consumption drops to 0.77W during s2idle.
> 
> [Regression Potential]
> Low, the patches only applied to specific nvme module, and from our
> test, the system is still stable.
> 
> [Misc]
> This issue should be fixed by the firmware, and we're pushing sk hynix
> to fix it. But before sk hynix find out how to solve it, we have to
> preserve these commits in our kernel for a while.
> BTW, the patches require pm_suspend_via_s2idle() function from below
> commit which is still under reviewing.
> https://lists.ubuntu.com/archives/kernel-team/2018-October/096141.html

Applied to unstable/master, thanks!



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