discrete card not powered down in Intel mode with legacy drivers
| Affects | Status | Importance | Assigned to | Milestone | |
|---|---|---|---|---|---|
| nvidia-prime (Ubuntu) |
New
|
Undecided
|
Unassigned | ||
Bug Description
This is the same issue as originally reported in bug 1765363 but that report is old and has a lot of extra data on it so it was requested that a new bug be opened if we were still having the issue.
So... I am still having the issue, at least with the 390 series drivers (my laptop has a Quadro 5400M).
Switching to Intel mode via either the GUI in nvidia-settings or via prime-select successfully moves the rendering to the Intel card but does not power down the discrete card, as evidenced by either power consumption in powertop in excess of 20W, or by manually checking /proc/acpi/bbswitch (shows ON).
Manually echoing off into /proc/acpi/bbswitch does turn the card off as can be seen from the power consumption drop.
ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: nvidia-prime 0.8.15
ProcVersionSign
Uname: Linux 5.8.0-40-generic x86_64
ApportVersion: 2.20.11-0ubuntu50.3
Architecture: amd64
CasperMD5CheckR
CurrentDesktop: ubuntu:GNOME
Date: Sun Jan 24 19:07:10 2021
Dependencies:
InstallationDate: Installed on 2021-01-24 (0 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
PackageArchitec
ProcEnviron:
TERM=xterm-
PATH=(custom, no user)
XDG_RUNTIME_
LANG=en_US.UTF-8
SHELL=/bin/bash
SourcePackage: nvidia-prime
UpgradeStatus: No upgrade log present (probably fresh install)
| Dan Robinson (dlrobinson) wrote | #1 |
| Dan Robinson (dlrobinson) wrote | #2 |
Well I played with this some more in Hirsute and I wonder if I may have jumped the gun.
If I give it a minute to idle the power usage drops down to about 11-12 watts, which is about 2W more than using bbswitch or disabling the card in BIOS.
Which suggests that power management is working and it's *probably* good enough since my battery is shot anyway; at least it's low enough to keep idle temps sane.
I'm thinking maybe we leave the bug open to see if the power management can be brought any closer, but if it can't I guess this could be closed too.