Screen glitches on Qualcomm SM8250 (freedreno) during wake from sleep and brightness change

[edkozuto]

Device: Retroid Pocket 5 (SM8250, Adreno 650, freedreno)
OS: Rocknix (Linux 7.0.11)
FEX version: from Rocknix Nightly 20260612

Symptoms:
Screen shows heavy glitching (artifacts, flickering, tearing) when:

Waking from sleep

Changing brightness (including brightness fade when idling)

Ocasionally on Steam launching process

Glitches only occur while Steam is running through FEX. All native ARM apps work fine. Without FEX, no glitches.

What I tried:

Panel driver delays (mipi_dsi_msleep(120) after exit_sleep_mode) — no effect

Gamescope flags (--adaptive-sync, --disable-vsync, --immediate-flips) — no effect

Disabling Gamescope entirely (Steam via Sway) — no effect

FEX ThunksDB: setting drm, Vulkan, GL to host passthrough — made it worse (screen blanks on brightness change)

Disabling XRandR, Steam backlight control, Steam fade — no effect

Logs:
Steam systemmanager.txt shows [display] Fade from queried backlight on resume. Kernel DRM debug (drm.debug=0x1ff) shows only DRM_IOCTL_SYNCOBJ_QUERY — no panel errors.

Workaround:
A systemd service does a double blank/unblank cycle on resume. Glitches appear briefly, then screen corrects itself.

Suspected cause:
FEX x86 DRM emulation races with freedreno during blank/unblank/gamma operations on resume.

[Sonicadvance1]

Try the ARM64 Steam client without involving FEX at all. There's guides online for getting it setup.

[edkozuto]

Try the ARM64 Steam client without involving FEX at all. There's guides online for getting it setup.

Yes, that works just fine, though there's no way to manipulate brightness at all.