The USB-C DisplayPort Alt Mode intermittently stops working on my EVO15-A8 (AMD 8845HS, BIOS N.1.14GOS07, EC 2.12.00). When the issue occurs, the EC/UCSI firmware refuses to negotiate DP Alt Mode -- the partner device is detected but the alt mode is never activated (active = no). USB data continues to work normally, only video output is affected.

The issue persists across reboots, cold boots, BIOS defaults reset, Live USB boot, different cables, different USB-C ports, and even a different monitor connected directly (no KVM). The only recovery method found is reflashing the BIOS+EC firmware via EFI shell, which is not an acceptable workaround for a recurring issue.

Full technical analysis with kernel logs, 18 failed remediation attempts, sysfs state dumps, and a detailed root cause analysis is available here: https://gist.github.com/gnespolino/81abd597153fd19aa2a039f66b8359a3

I would like to request either an EC firmware fix or at minimum an accessible EC reset mechanism (e.g. a BIOS menu option) so that a full firmware reflash is not required every time this happens.

Thank you