Re: long delay when using HMDI output on RS780

[Alex Deucher <alexdeucher@gmail.com>]

On Sat, May 7, 2011 at 8:15 PM, Thomas Fjellstrom <thomas@fjellstrom.ca> wrote:
> 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?

Most likely, the monitor doesn't like the hdmi packets it's getting
from the GPU.  If you don't need audio, boot 2.6.38 or newer with
radeon.audio=0

Alex

>
> --
> Thomas Fjellstrom
> thomas@fjellstrom.ca
>
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