Hi Ville, Ankit, Update on testing (Feb 14): After isolated testing of each patch on kernel 6.18.7, I can now definitively confirm:
- SCDC polling patch ALONE: Works perfectly ✓ - delay patch (150ms) ALONE: Screen remains black ✗ - Both patches together: Works (but delay is unnecessary) This definitively answers the question: approach #1 (Generic SCDC polling after port enable) is the correct solution. The v2 delay patch is NOT needed and should be disregarded. The SCDC polling aligns with HDMI 2.0 spec requirements and Windows behavior, making it the proper generic solution. Sorry for any confusion from my earlier messages. Thanks, Jerome Le sam. 7 févr. 2026 à 04:14, Jérôme Tollet <[email protected]> a écrit : > > Hi Ville, Ankit, > > Gentle ping on this thread - it's been about 10 days since my last > message in the thread (Jan 28). > > To recap, we have three potential approaches for this fix: > 1. Generic SCDC polling after port enable (current patch) - aligns > with Windows behavior > 2. Panel-specific quirk for affected displays (Cisco Desk Pro in my case) > 3. Fixed delay after SCDC config (my v2 patch from Jan 14) > > Testing showed the delay works at any placement in the modeset > sequence, suggesting this is a timing issue rather than > operation-specific. > I'm happy to implement whichever approach you prefer. Please let me > know which direction you'd like me to take this. > > Thanks, > Jerome > > > Le mer. 28 janv. 2026 à 15:42, Jérôme Tollet <[email protected]> a > écrit : > > > > Hi Ville, > > Following Ankit's response on January 21st where he suggested > > considering a panel-specific quirk instead of a generic solution, I > > wanted to get your input on the preferred approach. > > As a reminder, testing showed the delay works at any placement in the > > modeset sequence (all 4 test positions succeeded), suggesting this is > > a timing issue rather than being tied to a specific operation. > > > > Three approaches are available: > > 1. Generic SCDC polling after port enable - aligns with Windows > > behavior which also performs ~200ms SCDC poll post-enable > > 2. Panel-specific quirk for affected displays (Cisco Desk Pro in my case) > > 3. Fixed delay after SCDC config (my v2 patch from Jan 14) > > > > I'm happy with any approach that gets merged. > > > > Thanks > > Jerome
