I just switched to using HDMI with my media center, and its causing a 30+ second delay in the screen turning on, as well as a 7 second delay in the X startup when it tries to fetch the EDID information. Basically I don't get any picture at all once KMS initializes until after X has been up a few seconds.
The odd thing is the monitor seems to think something is going on, since it doesn't go to sleep or display its "No Signal" OSD, but just after X starts up, it pops up the "Input detected/switched" OSD, and the picture appears.
The bios, grub2 (in both text mode and graphics mode), and the initial linux kernel messages all display fine and immediately. Its only once KMS and radeondrmfb initializes that there's a problem (at least till X starts up).
I've just built with a vanila 2.6.38.4 kernel from the stable git repo, and have played with some EDID settings, trying to disable edid where I could thinking thats what caused the problem. That doesn't seem to be the case though. I also tried playing with the video= kernel option, trying to force disable VGA-1, and set a static mode for HDMI-A-1, but if I try, it seems to force disable HDMI-A-1 instead of force the mode.
With a DVI-D cable instead, the problem goes away.
Attached are the dmesg and xorg.log files for the latest boot with HDMI (no video= parameter, and EDID enabled, most settings at defaults).
What exactly would cause this, and is there a way I can fix it?