Bug: Timeline will not play (AMD RDNA2 GPUs)

[foxyllakora]

This issue is NOT about missing codecs

• I understand

Describe the bug

Timeline and media preview does not play. This looks a lot like #205 and #211 but I definitely do not have multiple GPUs, as shown by list-gpus

Steps to reproduce

1. Installed Davincibox on Bazzite using ujust install-resolve (Also later removed and and used setup.sh directly from github)
2. Activated Resolve
3. Load new project or an existing project
4. Import media or load timeline
5. Doesn't play (If I let it sit for a looong time, it sometimes will start playing, at like 2-4 fps)

Installation method used

setup.sh

OS Version

Bazzite 43

Desktop Environment

KDE Plasma

GPU Vendor

AMD

GPU Model

RX 6950 XT

CPU

Ryzen 9 5950X

CPU w/ integrated GPU?

No iGPU

DaVinci Resolve Free or DaVinci Resolve Studio

Studio

DaVinci Resolve version

20.3.2

Davincibox build (NOT the GitHub release number)

ghcr.io/zelikos/davincibox-opencl latest cda052c0a366 22 hours ago 2.68 GB

Extra context

I have tried a few thing. I've converted files to ProRes and DNxHD, installed (and removed) lib-mesaOpenCL, added my user to the video and render groups, used ujust install and setup.sh directly, nothing seems to make any difference. The only thing I've found interesting is that when i do run-davinci -c it crashes upon loading a project. Without the -c it behaves as described above, but with the flag enabled it always crashes on loading a project.

Here is my list-gpus

📦[foxyllakora@davincibox recordings]$ list-gpus Device: 0 Name: Advanced Micro Devices, Inc. [AMD/ATI] Navi 21 [Radeon™ RX 6950 XT] (Navi 21 [XFX Speedster MERC319 Radeon™ RX 6950 XT]) Default: yes Environment: DRI_PRIME=pci-0000_0b_00_0 VK_LOADER_DRIVERS_SELECT=*radeon* 📦[foxyllakora@davincibox recordings]$

And my gpu shown within Resolve

[foxyllakora]

Just stumbled on something weird that may help. If I'm trying to play the timeline, and I force the the cursor to update by repeatedly scrolling over a resizable element border, the timeline will play a single frame. So I can get it to play around 5 fps if I circle certain corners of elements. I'd record this behavior, but... as soon as OBS is open the timeline and preview NEVER update no matter what. As soon as OBS closes, it resumes updating the preview and timeline on cursor icon change

Also Youtube playback causes it to not update. And watching a Discord stream. Or really anything that updates the screen regularly. So it seems to be an issue with Resolve or the distrobox accessing the GPU resource in some way

[Wincohax]

Having the same issue with Bazzite-DX 43. installed from the ujust command.

My GPU is a RX 6600 XT.

I also use Davinci Resolve Studio. If I find something I'll update this comment.

Update: No current known workaround works. installing the full rocm suit nor using rustcl.

Rustcl crashes resolve in my case so I can't even test it to say it works or not.

[Wincohax]

Managed to Fix it thanks to enabling rocm logs.
Tried to read them and went to multiple layers till I went insane and went to claude asking for help LMAO.

if you launch resolve with HSA_ENABLE_SDMA=0 everything starts working fine.

According to AMD:

HSA_ENABLE_SDMA=0 causes host-to-device and device-to-host copies to use compute shader blit kernels, rather than the dedicated DMA copy engines. Compute shader copies have low latency (typically < 5 us) and can achieve approximately 80% of the bandwidth of the DMA copy engine.

This disables SDMA (the DMA copy engine) and forces the GPU shader blit path, which can actually be faster for large frame copies on RDNA2 without XNACK support.

Hope it helps anyone with the same problem.

[foxyllakora]

Managed to Fix it thanks to enabling rocm logs. Tried to read them and went to multiple layers till I went insane and went to claude asking for help LMAO.

if you launch resolve with HSA_ENABLE_SDMA=0 everything starts working fine.

According to AMD:

HSA_ENABLE_SDMA=0 causes host-to-device and device-to-host copies to use compute shader blit kernels, rather than the dedicated DMA copy engines. Compute shader copies have low latency (typically < 5 us) and can achieve approximately 80% of the bandwidth of the DMA copy engine.

This disables SDMA (the DMA copy engine) and forces the GPU shader blit path, which can actually be faster for large frame copies on RDNA2 without XNACK support.

Hope it helps anyone with the same problem.

This fixed it for me too! I think it's more of a workaround though, since I think the main culprit is OpenCL not fully working. I found before applying the above (and after, too) that trying to enable Remote Monitoring gives the error "OpenCL is not supported." This isn't a feature I intend to use so it doesn't affect me, I just found it when I was going crazy toggling everything I could to try and find some fix lol. But yea, that env variable works great for me