Fine-grained RTD3 with NVIDIA GeForce MX550

Graphics / Linux Linux
1

Hello, I have Lenovo ThinkPad T14 Gen 4 with Intel i7-1360P CPU and NVIDIA GeForce MX550 GPU. I use Arch Linux with kernel 6.8.1 and (closed-source) NVIDIA GPU drivers, version 550.54.14. I tried to enable fine-grained RTD3 following the instructions here.

However when I reboot the machine and inspect the file /proc/driver/nvidia/gpus/<Domain>:<Bus>:<Device>.<Function>/power I see:

Runtime D3 status:          Not supported
Video Memory:               Active

GPU Hardware Support:
 Video Memory Self Refresh: Not Supported
 Video Memory Off:          Supported

When I use NVreg_DynamicPowerManagement=0x01 option instead of NVreg_DynamicPowerManagement=0x02, reboot the machine and inspect the file again, I see:

Runtime D3 status:          Enabled (coarse-grained)
Video Memory:               Active

GPU Hardware Support:
 Video Memory Self Refresh: Not Supported
 Video Memory Off:          Supported

Contents of a file /etc/modprobe.d/nvidia.conf:

options nvidia_drm fbdev=1
options nvidia_drm modeset=1
options nvidia NVreg_EnableGpuFirmware=1
options nvidia NVreg_EnablePCIeGen3=1
options nvidia NVreg_EnableResizableBar=1
options nvidia NVreg_UsePageAttributeTable=1
options nvidia "NVreg_DynamicPowerManagement=0x02"
options nvidia NVreg_EnableS0ixPowerManagement=1

Contents of a file /etc/udev/rules.d/80-nvidia-rtd3.rules:

# Enable runtime power management for NVIDIA VGA/3D controller devices on driver bind.
ACTION=="bind", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x030000", TEST=="power/control", ATTR{power/control}="auto"
ACTION=="bind", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x030200", TEST=="power/control", ATTR{power/control}="auto"

# Disable runtime power management for NVIDIA VGA/3D controller devices on driver unbind.
ACTION=="unbind", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x030000", TEST=="power/control", ATTR{power/control}="on"
ACTION=="unbind", SUBSYSTEM=="pci", ATTR{vendor}=="0x10de", ATTR{class}=="0x030200", TEST=="power/control", ATTR{power/control}="on"

Please does the NVIDIA GeForce MX550 GPU support fine-grained RTD3? If yes, please is there some way how I can enable it?

Thank you very much and have a nice day.

nvidia-bug-report.log (208.4 KB)

2

It shouldn’t be necessary to set the value, it should default to 0x3, meaning “auto”.
Please check for a bios update.

3

Thanks for the reply. The laptop is running the latest BIOS. Please what would you recommend as the next steps? Contact Lenovo?

4

You might do that, though I don’t know if that will help. MX type mobile gpus are always lacking some features, don’t know if that expands to runtime pm capabilities.

5

Please are there some data sheets available for NVIDIA GeForce MX550, where I could find whether the fine-grained RTD3 is supported? I tried looking around on Google, but haven’t found any.

6

Btw when I don’t explicitly set the value of NVreg_DynamicPowerManagement and inspect the file cat /proc/driver/nvidia/params I see:

DynamicPowerManagement: 3

As expected. However when I inspect /proc/driver/nvidia/gpus/<Domain>:<Bus>:<Device>.<Function>/power I see:

Runtime D3 status:          Disabled by default
Video Memory:               Active

GPU Hardware Support:
 Video Memory Self Refresh: Not Supported
 Video Memory Off:          Supported

When I explicitly set the value of NVreg_DynamicPowerManagement to 0x01, at least the coarse-grained RTD3 seems to be enabled.

7

Sorry, forgot the MX550 is Turing based, so “auto” means “disabled”. So you really have to set the value manually and see what works.

8

Thanks. So if I explicitly set NVreg_DynamicPowerManagement=0x02 and get the result:

Runtime D3 status:          Not supported
Video Memory:               Active

GPU Hardware Support:
 Video Memory Self Refresh: Not Supported
 Video Memory Off:          Supported

Does it mean that MX550 does not support fine-grained RTD3 at all (is it a limitation of the hardware) or could it be a problem on Lenovo side - the necessary functionality is not implemented and it’s worth trying to contact Lenovo support so they can fix this issue?

9

IDK. Maybe switch to the nvidia-open driver, this now also supports runtime-pm and has some more info messages to print.

10

I managed to solve this by not using the NVreg_EnableGpuFirmware=1 option. When removed, the fine-grained RTD3 works. (Still using the closed-source NVIDIA drivers.) Please is this expected?

Runtime D3 status:          Enabled (fine-grained)
Video Memory:               Off

GPU Hardware Support:
 Video Memory Self Refresh: Supported
 Video Memory Off:          Supported
11

No, should work. Seems you found a bug with the firmware.

12

Ok thanks. So I guess the next step would be to report this bug via this page, right?

13

Yes, I think so.

14

Thank you very much for your help @generix :)