https://bugs.freedesktop.org/show_bug.cgi?id=47007
--- Comment #29 from Tvrtko Ursulin tvrtko.ursulin@onelan.co.uk 2012-03-15 08:34:48 PDT --- (In reply to comment #28)
(In reply to comment #26)
I'm not sure we necessarily want to do that. Even though they may have a shared ddc line, it would be nice to report the proper connected status.
What do you consider the proper connected status? With DVI-I made out of VGA-1 and DVI-1 in software, only one of them should be connected at a time, no?
I'm not sure what the right answer is.
Is it possible to have DVI-D + VGA breakout cable from a single DVI-I which would give two independent simultaneous outputs? If not then it looks to me only one KMS connector can be connected at a time.
What about the following:
DVI + VGA with shared ddc line. VGA connected and in use. User connects DVI port, gets hpd irq, detect called. hpd sense returns true, DVI is updated as connected, VGA is marked as disconnected. User then potentially loses the monitor they are currently using.
Are you implying DVI + VGA with shared DDC lines come as either one shared (DVI-I) connector, or two physical ones (DVI-? + VGA)? This is a very deep hole indeed...
Yes, the shared_ddc flag is only set of there are two different physical connectors that are both wired to the same ddc line (e.g., a separate VGA plug and HDMI plug). With DVI-I it's a single physical connector. DVI-I ports always have a single ddc line.
Hm, shared_ddc is also set with single physical DVI-I connector, at least on this motherboard.
Could you clarify what EDID do you get with two physical connectors which share DDC?