v0.40 engages dGPU

[Chris-1101]

mpv Information

mpv v0.40.0 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Mar 25 2025 17:58:20
libplacebo version: v7.349.0
FFmpeg version: n7.1
FFmpeg library versions:
   libavcodec      61.19.100
   libavdevice     61.3.100
   libavfilter     10.4.100
   libavformat     61.7.100
   libavutil       59.39.100
   libswresample   5.3.100
   libswscale      8.3.100

Other Information

- Linux version: Arch Linux
- Kernel Version: 6.13.8-arch1-1
- GPU Model: AMD Phoenix3 (integrated), NVIDIA AD106M GeForce RTX 4070 Max-Q (discrete)
- Mesa/GPU Driver Version: 4.6 (Compatibility Profile) Mesa 25.0.2-arch1.2
- Window Manager and Version: Hyprland v0.48.1
- Source of mpv: Arch official repos (extra)
- Latest known working version: 0.39
- Issue started after the following happened: after updating to 0.40

Reproduction Steps

Launch mpv via CLI or .desktop file.

Expected Behavior

Launching mpv with default options does not engage the discrete GPU.

Actual Behavior

Launching mpv after updating to 0.40, anyhow I've tried, will immediately engage the dGPU, even just via the .desktop file in standby mode without any decoding. I've also tried passing --no-config, --drm-device, and --vaapi-device (pointing these last two to the iGPU) to no avail.

After downgrading to 0.39, mpv doesn't engage the dGPU.

PS: I'm inspecting the state of the dGPU via the power_state file, located at /sys/bus/pci/devices/<dGPU_ID>/power_state on my distro. Using nvidia-smi also shows the mpv process registered with the nvidia GPU as both a compute and graphics process (Type C+G). Both of these have proven accurate in tracking dGPU usage in the past.

Log File

gpu_log.txt

Sample Files

No response

I carefully read all instruction and confirm that I did the following:

• I tested with the latest mpv version to validate that the issue is not already fixed.
• I provided all required information including system and mpv version.
• I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

[llyyr]

mpv will prefer dGPU over iGPU if both are available. You can make it use iGPU with --vulkan-device. Check with --vulkan-device=help to see what your iGPU's UUID is.

[Chris-1101]

@llyyr thanks that seems to work.

With --vulkan-device, dGPU is only engaged at startup and exit (which didn't happen in 0.39), but during playback it goes back to D3cold/suspended which is fine.

[kasper93]

With --vulkan-device, dGPU is only engaged at startup and exit (which didn't happen in 0.39), but during playback it goes back to D0 which is fine.

The main difference is that 0.39.0 was using gpu-api=opengl in which case your dGPU was probably not used. Also from your description is looks like Vulkan driver is waking up the dGPU when enumerating devices, during startup, which is reasonable, but probably not expected. Not sure why it does it again during destroying context, but not sure if mpv can do anything about this.

EDIT: https://gitlab.freedesktop.org/mesa/mesa/-/issues/11383

[Chris-1101]

@kasper93 understood, thanks for the additional context.

My device has a slight lag when enumerating devices, so startup takes a bit longer with vulkan, but setting --gpu-api=opengl solves that as well.

Thanks for the quick replies 🙏

[conspibro]

I just updated to v0.40.0 recently and had this issue too.

Setting gpu-api=opengl does help in my case too. Now my nvidia dGPU remains in D3cold state and mpv opens right up without delay.

Setting vulkan-device is redundant, since it defaults to my iGPU as per expected behaviour like in prior versions. Having it specified would wake up dGPU too, even if set to use iGPU. So just leave this flag out and just use gpu-api=opengl

[kasper93]

Please direct your request here https://gitlab.freedesktop.org/mesa/mesa/-/issues/11383 It's an improvement that is outside of mpv control. Or directly to NVIDIA if using proprietary drivers.

[iczero]

@conspibro It seems like the Nvidia Vulkan driver might need to be explicitly disabled by setting the env var VK_DRIVER_FILES. If you currently use hwdec=auto, you may also need to set it to hwdec=vaapi. After setting these, mpv no longer woke up the dGPU on my system.

export VK_DRIVER_FILES=/usr/share/vulkan/icd.d/intel_icd.x86_64.json:/usr/share/vulkan/icd.d/intel_icd.i686.json
mpv --hwdec=vaapi <file>