Bug 90301

Running similar tests in the Windows 8.1 partition, I can get to C3 state for PkgTemp. So something seems to be preventing this in Linux.

The issue isn't pstates its idle... closing this

to run an apples/apples comparison of Windows and Linux,
you'll nee to disable the Linux intel_idle so that Linux
uses acpi_idle like Windows does.  Only then can you compare
"C3 residency" -- since then they are both talking about ACPI C3,
not hardware C3.

eg.
boot with "intel_idle.max_cstate=0"
dmesg | grep idle
grep . /sys/devices/system/cpu/cpu0/cpuidle/*/*
to see what states ACPI is actually exporting
and then run turbostat.

The problem isn't so much intel_idle, the issued turned to be that I had to disable GFX with the IOMMU (intel_iommu=igfx_off) when this is set, now I get to Package Cstate of 6 and will get to 7 if display is shut off.

Right now, I disable the IGP and the laptop display only using the AMD GPU:

Boot options:

IMAGE=/boot/vmlinuz-4.2.0-0.rc3.git1.2.fc24.x86_64 root=UUID=f834b05c-55f3-407b-9a63-fc6b04d4c845 ro rhgb slub_debug=- cgroup_disable=memory console=tty0 console=ttyS0,115200n8 nmi_watchdog=0 i915.powersave=1 intel_iommu=igfx_off vfio_iommu_type1.allow_unsafe_interrupts=1 zswap.zpool=zsmalloc zswap.enabled=1 video=LVDS-1:d video=VGA-0:e pcie_aspm=off i915.enable_rc6=1 i915.enable_fbc=1 intel_iommu=on audit=0 radeon.gartsize=2048 LANG=en_US.UTF-8

Current run:

    Core     CPU Avg_MHz   %Busy Bzy_MHz TSC_MHz     SMI  CPU%c1  CPU%c3  CPU%c6  CPU%c7 CoreTmp  PkgTmp Pkg%pc2 Pkg%pc3 Pkg%pc6 Pkg%pc7 PkgWatt CorWatt GFXWatt
       -       -       3    0.35     963    2893       0    6.67    0.09    0.28   92.61      48      51    0.70    0.30   80.30    0.00    0.92    0.04    0.00
       0       0       3    0.36     963    2893       0    0.44    0.18    0.00   99.02      46      51    0.70    0.30   80.30    0.00    0.92    0.04    0.00
       0       4       0    0.02     940    2893       0    0.77
       1       1       7    0.77     957    2893       0    0.95    0.12    0.00   98.16      48
       1       5       0    0.02    1182    2893       0    1.70
       2       2       5    0.49     964    2893       0    8.47    0.01    1.11   89.92      47
       2       6       1    0.08     888    2893       0    8.88
       3       3      10    1.08     969    2893       0   15.54    0.06    0.00   83.32      48
       3       7       0    0.01     950    2893       0   16.61

As the problem is that system is unable to enter PC3 and deeper package states when gfx DMAR unit is enabled, please file a bug at bugs.freedesktop.org instead.

Which component? i915 for kernel DRM side?

Well, I don't know.
Please feel free to try any component. They will redirect you to the right component if you file it wrongly. :p

Ok, I'm still unsure fully, as enabling gfx DMAR when HSW GPU active still causes package state to not go past PC3, but either way, I'll file with fdo folks.

So, this problem still exists with using the iGPU + dGPU on the latop: 

Using these boot options:

root=UUID=f834b05c-55f3-407b-9a63-fc6b04d4c845 ro rhgb slub_debug=- cgroup_disable=memory console=tty0 console=ttyUSB0,9600n8 nmi_watchdog=0 audit=0 amdgpu.gartsize=8192 amdgpu.vm_size=16 amdgpu.powerplay=1 amdgpu.exp_hw_support=1 rd.driver.blacklist=radeon amdgpu.dal=1 video=eDP-1:d video=VGA-1:e resume=/dev/sda7 intel_iommu=igfx_off i915.enable_rc6=1 i915.enable_fbc=1 pcie_aspm=off

I can only reach PC2 states, pretty much 99% of PC2 states.


I've set to low power the SATA controller ports

echo 'min_power' > '/sys/class/scsi_host/host1/link_power_management_policy';
echo 'min_power' > '/sys/class/scsi_host/host0/link_power_management_policy';
echo 'min_power' > '/sys/class/scsi_host/host2/link_power_management_policy';
echo 'min_power' > '/sys/class/scsi_host/host3/link_power_management_policy';
echo 'min_power' > '/sys/class/scsi_host/host4/link_power_management_policy';
echo 'min_power' > '/sys/class/scsi_host/host5/link_power_management_policy';

This is still not good on 4.9-rc4+

Created attachment 244551 [details]
turbostat debug dump

Created attachment 244561 [details]
Powertop report

Powertop report

If I disable the iGPU I have no problem reaching PC6 state, so something the iGPU is doing?

Seems it just takes alot longer to get to PC6, but it finally does. Closing.