On 2/14/2026 9:47 PM, Jérôme Tollet wrote:
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.
Thanks Jerome for testing.
Lets have all discussion in the original thread on the patch [1].
It seems your recent mails are on a separate thread.
Regards,
Ankit
[1]
https://lore.kernel.org/intel-xe/[email protected]/
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
