On Monday, June 21st, 2021 at 08:43, Tomohito Esaki [off-list ref] wrote:

Virtual DRM splits the overlay planes of a display controller into multiple
virtual devices to allow each plane to be accessed by each process.
This makes it possible to overlay images output from multiple processes on a
display. For example, one process displays the camera image without compositor
while another process overlays the UI.

Updating the KMS state from multiple processes doesn't sound like a
good idea. This opens up synchronization and global device limits
issues.

Are you aware of DRM leasing?