https://bugs.freedesktop.org/show_bug.cgi?id=49943
--- Comment #1 from Harald Judt h.judt@gmx.at 2012-05-18 06:35:44 PDT --- Ok, I've run radeonreg, here is the output:
Before HDMI connected: 0x601c 0x00000000 (0) 0x6028 0x06000012 (100663314) 0x6034 0x00000012 (18) 0x6040 0x00000000 (0) 0x604c 0x00000000 (0) 0x6058 0x00000000 (0)
HDMI connected: 0x601c 0x00000000 (0) 0x6028 0x06000012 (100663314) 0x6034 0x00000012 (18) 0x6040 0x00000000 (0) 0x604c 0x00000000 (0) 0x6058 0xff000012 (-16777198)
HDMI disconnected: 0x601c 0x00000000 (0) 0x6028 0x06000012 (100663314) 0x6034 0x00000012 (18) 0x6040 0x00000000 (0) 0x604c 0x00000000 (0) 0x6058 0xff0ff000 (-15732736)
The value of reg 0x6058 changes (HDMI-0). As you can see, after HDMI has been disconnected, it is different from the original value (0). I suspect that there is some problem with this?