linux-kernel - Re: long delay when using HMDI output on RS780

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Date:	Mon, 9 May 2011 13:50:42 -0600
From:	Thomas Fjellstrom <thomas@...llstrom.ca>
To:	dri-devel@...ts.freedesktop.org
Cc:	linux-kernel@...r.kernel.org
Subject: Re: long delay when using HMDI output on RS780

On May 7, 2011, Thomas Fjellstrom 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?

I've been playing around with it more, and got it to not blank the screen 
after KMS init, /once/. So far no luck repeating that success.

I've tried late, and early kms init, and currently have the radeon module and 
firmware compiled into the kernel. Boot times at least are fairly decent, about 
8-10s till X starts, but about 25-35s till anything shows up.

Some strangeness, I have the kernel set to force the hdmi output to on, with a 
very specific mode, that X tends to like, the vga port is forced disabled. X is 
set to ignore EDID, and also set to that specific mode that it tends to auto 
set itself. Regardless X still wants to pause for 7s 2-3 times while 
processing EDID info.

I've attached the new dmesg and xorg logs from the latest attempts.

Note, this only happens with KMS, with HDMI. disabling KMS, or using DVI makes 
the problem go away. Even grub's own graphical mode works fine, its only once 
KMS inits that things go bad, and its not till after X is up for a few seconds 
that something displays on my screen.

-- 
Thomas Fjellstrom
thomas@...llstrom.ca

View attachment "chauncey.dmesg" of type "text/plain" (55144 bytes)

View attachment "Xorg.0.log" of type "text/x-log" (62159 bytes)