SteamOS 3.8.16 Stable: Intermittent black screen after waking from sleep in Desktop Mode

Your system information

• Steam client version: 1782861641
• SteamOS version: 3.8.16
• Opted into Steam client beta?: No
• Opted into SteamOS beta?: No
• Have you checked for updates in Settings > System?: Yes
• Steam Deck Model: Steam Deck LCD

Please describe your issue in as much detail as possible:

After updating from SteamOS 3.7 to SteamOS 3.8.16 Stable, my Steam Deck intermittently fails to resume from sleep when the system was put to sleep while in Desktop Mode.

The power LED becomes solid white, indicating that the system has resumed, but the display remains black and the system cannot be recovered without holding the power button to force a shutdown.

So far, I have only observed this issue when the Deck was put to sleep from Desktop Mode. I have not been able to reproduce it in Gaming Mode despite repeatedly testing suspend/resume there.

The issue is intermittent. Sometimes it happens on the first suspend/resume cycle, other times it may take several days before occurring.

Expected result: Desktop Mode resumes normally.

Actual result: After waking, the power LED is solid white, but the display remains black. The system cannot be recovered without holding the power button to force a shutdown.

Steps for reproducing this issue:

1. Boot Steam Deck normally.
2. Switch to Desktop Mode (KDE Plasma on Wayland).
3. Put the Deck to sleep.
4. Wake the Deck.
5. Repeat as necessary.

The issue is intermittent and cannot be reproduced on every suspend/resume cycle.

Troubleshooting Performed:

• Happens docked and undocked.
• Wake Movie disabled.
• Storage Maintenance completed.
• Decky Loader completely removed.
• All Decky plugins removed.
• CryoUtilities reverted to SteamOS defaults.
• Happens even with no applications open in Desktop Mode.
• Not related to sleep duration.
• Gaming Mode has survived repeated suspend/resume testing without reproducing the issue.

Additional Information:

The issue only started after updating from SteamOS 3.7 to SteamOS 3.8.16 Stable. I collected system logs after the forced reboot. I did not notice any obvious amdgpu GPU reset or timeout messages, but I can provide the logs if they would be useful.

Begin with the listed suspend/resume steps in SteamOS 3.8.16 Stable, focusing on Desktop Mode and repeating the intermittent cycle. Review the system logs collected after a forced reboot and compare docked and undocked behavior. Done means Desktop Mode resumes normally without requiring a forced shutdown.