Video Memory Leak on dGPU while rendering Hyprland on iGPU when external display gets plugged in

[Rabcor]

Migrating from hyprwm/Hyprland#10219 (There is a lot more info in there)

I am on a laptop with an amd iGPU and an nvidia dGPU, I am rendering Hyprland on the iGPU but when I plug in an external HDMI monitor the Hyprland process' vram usage increases for the dGPU.

I use nvidia-smi (official utility) to analyze vram usage.

On sway, the sway process uses the same amount of vram on the dgpu before, during and after plugging in the external display.

Before during and after plugging in the display and removing it this number never changes.

On Hyprland, the hyprland process uses more vram after the display is plugged in, and it never releases this vram after it claims it. Plugging and unplugging the monitor more times wil inflate Hyprland's vram usage further each time the display gets plugged in.

After running Hyprland for a few days plugging the monitor in and out multiple times throughout that period this is the current vram usage. It started out at 3MiB on boot.

The way this laptop model is set-up, the HDMI port belongs to the dGPU, but since I'm rendering on the iGPU the display gets passed off to the iGPU after it's plugged in.

inxi snippet

Graphics:
  Device-1: NVIDIA GA104 [Geforce RTX 3070 Ti Laptop GPU] vendor: ASUSTeK
    driver: nvidia v: 570.144 alternate: nouveau,nvidia_drm non-free: 550-570.xx+
    status: current (as of 2025-04; EOL~2026-12-xx) arch: Ampere code: GAxxx
    process: TSMC n7 (7nm) built: 2020-2023 pcie: gen: 1 speed: 2.5 GT/s
    lanes: 8 link-max: gen: 4 speed: 16 GT/s lanes: 16 ports: active: none
    off: HDMI-A-1 empty: DP-1,eDP-1 bus-ID: 01:00.0 chip-ID: 10de:24a0
    class-ID: 0300
  Device-2: Advanced Micro Devices [AMD/ATI] Rembrandt [Radeon 680M]
    vendor: ASUSTeK driver: amdgpu v: kernel arch: RDNA-2 code: Navi-2x
    process: TSMC n7 (7nm) built: 2020-22 pcie: gen: 4 speed: 16 GT/s lanes: 16
    ports: active: eDP-2 empty: DP-2, DP-3, DP-4, DP-5, DP-6, Writeback-1
    bus-ID: 06:00.0 chip-ID: 1002:1681 class-ID: 0300 temp: 57.0 C
  Display: wayland server: X.org v: 1.21.1.16 with: Xwayland v: 24.1.6
    compositors: 1: Hyprland v: 0.49.0-4-g60cd5b7a4 2: Sway v: 1.10.1 driver: X:
    loaded: amdgpu dri: radeonsi gpu: amdgpu,nvidia,nvidia-nvswitch
    display-ID: 1
  Monitor-1: HDMI-A-1 model: Sony TV 00 serial: <filter> built: 2019
    res: 3840x2160 dpi: 61 gamma: 1.2 size: 1600x900mm (62.99x35.43")
    diag: 1836mm (72.3") ratio: 16:9 modes: max: 3840x2160 min: 640x480
  Monitor-2: eDP-2 model: BOE Display 0x0a69 built: 2021 res: 2560x1440
    dpi: 171 gamma: 1.2 size: 381x214mm (15x8.43") diag: 437mm (17.2")
    ratio: 16:9 modes: max: 2560x1440 min: 640x480
  API: EGL v: 1.5 hw: drv: nvidia drv: amd radeonsi platforms: device: 0
    drv: nvidia device: 1 drv: radeonsi gbm: drv: kms_swrast surfaceless:
    drv: nvidia wayland: drv: radeonsi x11: drv: radeonsi
  API: OpenGL v: 4.6.0 compat-v: 4.5 vendor: amd mesa v: 25.0.5-arch1.1
    glx-v: 1.4 direct-render: yes renderer: AMD Radeon 680M (radeonsi rembrandt
    LLVM 19.1.7 DRM 3.61 6.14.6-arch1-1) device-ID: 1002:1681 memory: 500 MiB
    unified: no
  API: Vulkan v: 1.4.313 layers: 12 device: 0 type: integrated-gpu name: AMD
    Radeon 680M (RADV REMBRANDT) driver: mesa radv v: 25.0.5-arch1.1
    device-ID: 1002:1681 surfaces: N/A
  Info: Tools: api: eglinfo, glxinfo, vulkaninfo
    gpu: nvidia-settings,nvidia-smi wl: swaymsg,wdisplays x11: xprop,xrandr

This may have no relevance to the issue at all but I figured I should include that information just in case if it is.

Because of this setup, some vram is always used on the dGPU when a monitor is plugged into this port, even on sway, however the difference between Hyprland and sway is that the sway process consumes none of that vram whereas the Hyprland process consumes somewhere in the range of 100% of that vram (so when a display is plugged in on Hyprland roughly 2x the amount of vram gets used on the dGPU compared to when on sway)

[vaxerski]

I'd guess that for some reason KMS imported buffers dont get dropped somehow. Gotta check the mgpu swapchains. I don't have a multi-gpu system, but I know @gulafaran has. Tom, if you wanna look into this, feel free

[Xaunther]

I am experiencing the same issue with the arch aquamarine package (version 0.8.0-4). However, I've tried with the latest main branch commit and the issue appears to be gone.

In my case, the vram didn't decrease when unplugging and increased by ~20MiB with every plugging in of the display. Now I can see a decrease of ~10MiB when unplugging and then it goes back to the original vram when plugged in, so it seems like it doesn't leak anymore.

Probably one of the latest MRs solved the issue. I'll do the exercise of compiling the 0.8.0 version and report back with my findings.

EDIT: I compiled version 0.8.0 and the problem comes back. So I'll go back to using main branch until it gets released. 😄

[Rabcor]

I have upgraded to a new laptop and found the problem is still the same (it has relatively the same graphical setup; amd igpu, nvidia dgpu, and they're muxed on this one too)

I have finally gotten around to trying the git build to verify @Xaunther s claim.

My findings are that while the worst part of the issue is fixed. There is still some memory leaking, but it's contained now. It doesn't increase everytime the monitor is plugged in anymore, only the first time it is plugged in does vram get permanently allocated to the hyprland process. The second time it is plugged in, half the amount of memory is allocated to the process again, however after unplugging it again the extra memory is released properly.

Also do keep in mind that as I said in my OP, on sway no vram gets allocated at all to the sway process when plugging in extra monitors (extra vram gets used, just not by the process, it's all handled by the drivers instead, this behavior would be the ideal solution)

Anyhow to more clearly showcase what happens in my testing on the git build:

1. On startup (laptop monitor only):

Mon Jun 30 21:35:36 2025       
+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64                 Driver Version: 575.64         CUDA Version: 12.9     |
|-----------------------------------------+------------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA GeForce RTX 5080 ...    On  |   00000000:01:00.0 Off |                  N/A |
| N/A   43C    P8              7W /   80W |      23MiB /  16303MiB |      0%      Default |
|                                         |                        |                  N/A |
+-----------------------------------------+------------------------+----------------------+
                                                                                         
+-----------------------------------------------------------------------------------------+
| Processes:                                                                              |
|  GPU   GI   CI              PID   Type   Process name                        GPU Memory |
|        ID   ID                                                               Usage      |
|=========================================================================================|
|    0   N/A  N/A           36140      G   Hyprland                                  3MiB |
+-----------------------------------------------------------------------------------------+

2. External monitor plugged in:

+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64                 Driver Version: 575.64         CUDA Version: 12.9     |
|-----------------------------------------+------------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA GeForce RTX 5080 ...    On  |   00000000:01:00.0  On |                  N/A |
| N/A   45C    P8              9W /   80W |      64MiB /  16303MiB |      0%      Default |
|                                         |                        |                  N/A |
+-----------------------------------------+------------------------+----------------------+
                                                                                         
+-----------------------------------------------------------------------------------------+
| Processes:                                                                              |
|  GPU   GI   CI              PID   Type   Process name                        GPU Memory |
|        ID   ID                                                               Usage      |
|=========================================================================================|
|    0   N/A  N/A           36140      G   Hyprland                                 23MiB |
+-----------------------------------------------------------------------------------------+

3. External monitor unplugged:

+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64                 Driver Version: 575.64         CUDA Version: 12.9     |
|-----------------------------------------+------------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA GeForce RTX 5080 ...    On  |   00000000:01:00.0 Off |                  N/A |
| N/A   45C    P8              7W /   80W |      44MiB /  16303MiB |      0%      Default |
|                                         |                        |                  N/A |
+-----------------------------------------+------------------------+----------------------+
                                                                                         
+-----------------------------------------------------------------------------------------+
| Processes:                                                                              |
|  GPU   GI   CI              PID   Type   Process name                        GPU Memory |
|        ID   ID                                                               Usage      |
|=========================================================================================|
|    0   N/A  N/A           36140      G   Hyprland                                 23MiB |
+-----------------------------------------------------------------------------------------+

4. External monitor plugged in again:

+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64                 Driver Version: 575.64         CUDA Version: 12.9     |
|-----------------------------------------+------------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA GeForce RTX 5080 ...    On  |   00000000:01:00.0  On |                  N/A |
| N/A   45C    P8             15W /  105W |      74MiB /  16303MiB |      0%      Default |
|                                         |                        |                  N/A |
+-----------------------------------------+------------------------+----------------------+
                                                                                         
+-----------------------------------------------------------------------------------------+
| Processes:                                                                              |
|  GPU   GI   CI              PID   Type   Process name                        GPU Memory |
|        ID   ID                                                               Usage      |
|=========================================================================================|
|    0   N/A  N/A           36140      G   Hyprland                                 33MiB |
+-----------------------------------------------------------------------------------------+

5. External monitor unplugged again:

+-----------------------------------------------------------------------------------------+
| NVIDIA-SMI 575.64                 Driver Version: 575.64         CUDA Version: 12.9     |
|-----------------------------------------+------------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id          Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |           Memory-Usage | GPU-Util  Compute M. |
|                                         |                        |               MIG M. |
|=========================================+========================+======================|
|   0  NVIDIA GeForce RTX 5080 ...    On  |   00000000:01:00.0 Off |                  N/A |
| N/A   45C    P8              7W /   80W |      44MiB /  16303MiB |      0%      Default |
|                                         |                        |                  N/A |
+-----------------------------------------+------------------------+----------------------+
                                                                                         
+-----------------------------------------------------------------------------------------+
| Processes:                                                                              |
|  GPU   GI   CI              PID   Type   Process name                        GPU Memory |
|        ID   ID                                                               Usage      |
|=========================================================================================|
|    0   N/A  N/A           36140      G   Hyprland                                 23MiB |
+-----------------------------------------------------------------------------------------+

Losing 20-30MiB of vram is a lot more tolerable than losing 20MiB of vram everytime a 1080p monitor is plugged in until the computer or hyprland process is restarted. Since my new laptop has twice as much vram as my old one this is more or less acceptable to me too (last laptop ran out of vram a lot, this one does not, at least not yet)

What's interesting to me though is that my laptops internal display is 1440p but the external display in this test is 1080p (in the OP I had a 4k external display); Hyprland is only using 3MiB of vram for the 1440p display, but 20-30MiB for the 1080p one 🤔 that's odd isn't it? It kinda seems like Hyprland is behaving like sway does when only the internal monitor is in use, and the odd behavior only happens when multiple displays are in play.

Unfortunately plugging in the display before starting hyprland does not affect the issue (it'll just start at 23MiB VRAM use on the process instead of on 3MiB).

If we look at the numbers of total vram usage, we can see that on startup without hyprland 20MiB vram is used, and after plugging in a second monitor, if we exclude the hyprland process vram usaage it'd be 40MiB, implying that both the 1440p and 1080p monitors use 20MiB vram each.