Re: [PATCH] imx-drm: imx-hdmi: fix hdmi hotplug detection initial state

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Mon, Jun 09, 2014 at 11:29:28AM -0300, Fabio Estevam wrote:
> On Mon, Jun 9, 2014 at 11:06 AM, Russell King - ARM Linux
> <linux@arm.linux.org.uk> wrote:
> 
> > Please check the status in /sys/class/drm/card0-HDMI-A-1/status.  This
> > should report the current state of the hotplug detection.
> 
> /sys/class/drm/card0-HDMI-A-1/status returns the correct state for
> HDMI cable connection.

Good, so that means we're reporting the correct status to the DRM layer.
Please post the kernel boot messages, one with the HDMI cable disconnected,
and one with a HDMI sink connected.

> The HDMI undetected issue I am seeing on sabresd seems to be related
> to the simultaneous usage of HDMI and LVDS.
> 
> If I remove the ldb node from the imx6qdl-sabresd.dtsi, then the HDMI
> cable is correctly detected and HDMI is shown right after boot.

I wonder if the problem is that HDMI and LVDS are interfering with each
other wrt the required pixel clock, and LVDS is winning.  If we have
HDMI enabled, many HDMI sinks will only work if we set one of their
supported modes (with the dot clock within 1% - though some sinks are
more lenient).

I think the Novena people have run into this issue, but I've not seen
much in the way of contributions back, despite them making use of my
patches...

-- 
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