(In reply to Michel Dänzer from comment #73)
> Looks like some client repeatedly calls XForceScreenSaver (probably to
> prevent the monitors from blanking), which results in the DPMS property
> getting re-set over and over. Nicholas, maybe the kernel could ignore such
> no-op property "updates"?

Even if it's no-op update it's still going to be locking the connector and
potentially blocking other commits from occurring so ideally the client
userspace wouldn't be dong this.

I can try writing up a patch that doesn't lock everything if the connector
state hasn't change at the very least but I'm not sure if it will fully address
the issue or not.