APPLIED(B,C): [PATCH 0/1][SRU][B][C][D][OEM-B]PC SN720 NVMe WDC 256GB consumes more power in S2Idle than during long idle

[Stefan Bader]

On 08.01.19 07:03, Khaled Elmously wrote:
> On 2018-11-29 15:44:23 , 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.
>> https://lists.ubuntu.com/archives/kernel-team/2018-November/096832.html
>>
>> BugLink: https://bugs.launchpad.net/bugs/1805775

Bug report did not reflect the applied state. Actually it was in rather bad shape:

1. No task for the linux source (no nominations for bionic and cosmic there)
2. Nomination for bionic/linux-oem not accepted.

>>
>> [Impact]
>> 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
>>
>> [Fix]
>> 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.
>>
>> [Test]
>> 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.
>>
>> AceLan Kao (1):
>>   SAUCE: pci/nvme: prevent WDC PC SN720 NVMe from entering D3 and being
>>     disabled
>>
>>  drivers/nvme/host/pci.c | 2 ++
>>  drivers/pci/quirks.c    | 1 +
>>  2 files changed, 3 insertions(+)
>>
>> -- 
>> 2.17.1
>>
>>
>> -- 
>> kernel-team mailing list
>> kernel-team at lists.ubuntu.com
>> https://lists.ubuntu.com/mailman/listinfo/kernel-team
> 


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