After upgraded two laptops to 11.10, HDMI and Display ports stopped to work. Symptoms on each (btw. it used to work with 11.04 on both):
laptop Dell Inspiron 1525 (HDMI, Intel GMX 3100):
- after HDMI cable is plugged in, screen is corrupted (no panel, no icons), system is unresponsive, TV set receives some signal, but only blue screen and some regular ticks can be heard. Unplugging the cable system recovers. No logs were checked.
Thinkpad W510 (DisplayPort, NVidia). Simple "Screens" utility does not recognizes TV set, but this is something to do with the differences between Nvidia driver API and the one expected from the utility, as far I could spot on the net. However, using Nvidia-settings, TV is recognized, but cannot be enabled and used. Beside that, touch pad freezes after HDMI2DisplayPort connector is plugged in the laptop (not immediately, but after few seconds - probably after some handshake with the TV set crashes).
It is strange that no such bug reports can be found on the net. So, I guess it is something wrong on our laptops only, but would appreciate some hints (i.e. any known changes recently related to HDMI, Display Port, X-Windows, kernel... wherever I should take a look and fix the issue).