Bug 217841
| Summary: | upstream linux cannot achieve package C8 power saving | ||
|---|---|---|---|
| Product: | Power Management | Reporter: | Brett Hassall (brett.hassall) |
| Component: | Run-Time-PM | Assignee: | Rafael J. Wysocki (rjw) |
| Status: | NEW --- | ||
| Severity: | normal | ||
| Priority: | P3 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | Subsystem: | ||
| Regression: | No | Bisected commit-id: | |
| Attachments: | patch to apply 3 Ubuntu fixes to enable kernel to achieve package c8 | ||
Neglected to say, laptop is: Laptop is a HP 15s-fq4011TU 11th Gen (Tiger Lake) Intel with (from lspci) Realtek Semiconductor Co., Ltd. RTL8822CE 802.11ac PCIe Wireless Network Adapter and Intel Corporation Volume Management Device NVMe RAID Controller. It makes sense to email the maintainer of this subsystem, their mailing list and even LKML or it's quite possible this bug report will never be noticed or acted upon. Ubuntu has reverted the 3 fixes upon which the attached patch is based. These 3 fixes were replaced by 2 new fixes that I can confirm achieve package C8 on my HP 15s-fq4011TU 11th Gen (Tiger Lake) with (from lspci) Intel Corporation Volume Management Device NVMe RAID Controller. There is significantly less code in the 2 new fixes so I don't recommend trying to use the attached patch. I no longer have regular access to the HP 15s however upstream 6.5 booted on a Dell Latitude 5530 also cannot achieve package C8 power saving. The Dell has (from lspci): Intel Corporation Volume Management Device NVMe RAID Controller, & Non-Volatile memory controller: SK hynix Device 1d59 (rev 03). As a workaround, running the following commands on the Dell allows pkg C8 to be reached: nvme=10000:e1:00.0 ctlr=10000:e0:06.0 sudo setpci -s $nvme CAP_EXP+0x10.B=0x42 sudo setpci -s $ctlr CAP_EXP+0x10.B=0x42 sudo setpci -s $nvme ECAP_L1PM+0x8.B=0x0c sudo setpci -s $ctlr ECAP_L1PM+0x8.B=0x1c I can comfirm the Dell with the 2 new Ubuntu fixes also achieves package C8. |
Created attachment 304981 [details] patch to apply 3 Ubuntu fixes to enable kernel to achieve package c8 v6.5 (and at least v5.15, v5.19 and v6.4 as well) will not go to a higher power saving level than package C3. With the inclusion of a patch that combines 3 Ubuntu commits related to VMD ASPM & LTR, package C8 is used.