Support CRTCs with multiple encoders/connectors
Affected version
Linux 6.6 with Mutter 45
Both Xorg and Wayland are affected
Bug summary
Aspeed graphics chips are mostly used in servers and some embedded systems. The chips are combined with a BMC that allows to watch the display's output remotely. In Linux 6.6, we've added a second encoder/connector for Aspeed hardware.
That newly added second output represents the BMC. It is always a mirror/clone of the first output.
Mutter does not work with the second output. It starts, but it is then impossible to change resolution on any of the outputs, or do anything at all in the Settings' display dialog.
Steps to reproduce
- Happens on Aspeed hardware.
- You need Linux 6.6
- In Gnome, go to Settings and try to configure the display.
What happened
Mutter does allow to change the output's configuration. It permanently shows a warning that the configuration is incompatible.
What did you expect to happen
I would expect to at least be able to configure the VGA/DP/DVI configuration as usual.
Relevant logs, screenshots, screencasts etc.
The affected system is in drmdb at https://drmdb.emersion.fr/snapshots/4c406f948ee9