Bug 905745

Summary:	gui-wm/sway: sometimes the system completely lost the HDMI output signal after switching HDMI sources using a HDMI switch several times.
Product:	Gentoo Linux	Reporter:	Xuesong Yan <yan_xuesong>
Component:	Current packages	Assignee:	Matthew Thode ( prometheanfire ) <prometheanfire>
Status:	UNCONFIRMED ---
Severity:	minor	CC:	speedjack95, yan_xuesong
Priority:	Normal
Version:	unspecified
Hardware:	AMD64
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Xuesong Yan 2023-05-05 08:07:44 UTC

When sharing a monitor with a HDMI switch, repeatedly switching the HDMI source among connected machines will lead to a blank screen without output signals for a box running a sway compositor. 

The issue can be observed on AMD GPUs (Rx 6600 / Rx 460). 

Reproducible: Always

Steps to Reproduce:
1. Compiles the sys-auth/seatd with the USE flags "server" and "builtin" disabled.
2. Shares the monitor with a HDMI switch (N sources connected to multiple machines, 1 output connected to the monitor)
3. Switching the HDMI source repeatedly.

Actual Results:  
Blank screen, the monitor shows its debug message "no HDMI output".

Expected Results:  
Working HDMI output.

After add the builtin/server USE flag to sys-auth/seatd, the bug seems to be fixed. The ebuild should be updated to enforce the dependency of related USE flags.