Additional structured testing results (regression window identified): After systematic testing across multiple mainline kernels, I was able to narrow the behavior down more precisely.
Hardware: - GPU: AMD Radeon R9 380 (Tonga, amdgpu) - HDMI connection - Motherboard: Gigabyte B450 AORUS PRO WIFI - CPU: Ryzen 5 5500 - Session: X11 Kernel comparison (mainline builds): 6.12.74 (LTS series): - System fully stable. - HDMI works normally. - Suspend/resume works reliably (multiple cycles tested). - No EDID errors observed. - No black screen after resume. 6.13.12: - First suspend/resume usually succeeds. - Second suspend often fails: black screen, no HDMI signal. - Keyboard becomes unresponsive. - Requires hard reboot. - Intermittent behavior. 6.14.x and newer (including 6.17 previously tested): - More frequent suspend failures. - Black screen on resume. - Occasional “HDMI Out of Range” message during early boot. - dmesg previously showed: amdgpu: [drm] *ERROR* HDMI-A-1: probed a monitor but no|invalid EDID Important observation: 6.12 works reliably without forcing amdgpu.dc=0. The issue appears between 6.12 → 6.13, suggesting a regression introduced in that window affecting HDMI reinitialization or EDID handling during resume. Power state notes: - Deep (S3) suspend used. - Forcing s2idle worsened behavior. - Disabling USB wake reduced spurious wake events but did not solve resume issue. Conclusion: This does not appear to be a random hardware instability, as 6.12 remains stable under identical conditions. The regression likely affects display reinitialization (DC/DRM layer) for Tonga-class GPUs over HDMI. I am willing to test patches, boot parameters, or debug builds if needed. My goal is to help narrow this down and contribute useful data for resolving the regression. Thank you for your work on the kernel and AMDGPU stack. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2142389 Title: amdgpu (R9 380) fails to resume from suspend (deep sleep) – black screen, requires hard reboot To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2142389/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
