imx-drm: Add HDMI support

[Shawn Guo]

On Mon, Oct 21, 2013 at 02:17:58PM +0100, Russell King - ARM Linux wrote:
> On Mon, Oct 21, 2013 at 08:36:55PM +0800, Shawn Guo wrote:
> > On Mon, Oct 21, 2013 at 10:34:48AM +0100, Russell King - ARM Linux wrote:
> > > However, the IPU is more stable with switching to bypass while it relocks
> > > than not.
> > 
> > As far as I know, FSL kernel has always been doing relock without
> > switching to bypass, and I haven't heard unstable IPU issue from their
> > testing.  Do you have a case that I can set up here to see the issue?
> 
> export DISPLAY=:0
> while :; do
>   xrandr -s 1280x720 -r 50
>   sleep 5
>   xrandr -s 1280x720 -r 60
>   sleep 5
> done

Sorry, it took me a long time to set up this test on xubuntu 13.10.
Building an image using your cubox-i branch, I can still see the above
test plays my HDMI device to death quite easily.  That said, I'm not
sure if the BYPASS handling in .set_rate() does help the unstable issue
we're seeing.

BTW, the xubuntu session can crash quite easily here if I play the
desktop a little bit, dragging a window and moving it around, popping
up a dialog, or something.

Shawn

> 
> is one way.  Another way is to switch between all possible resolutions
> supported by the connected device, keeping each resolution for 30 seconds
> a time.  Normally after one or two run-throughs, the IPU will be deader
> than the parrot in Monty Python's parrot sketch, requiring a reboot to
> get it working again.
> 
> As I've said previously, when it gets into this state, all the status
> registers I can find report that all FIFOs in the IPU are sitting in
> their empty state.  The TMDS clock is correct, and the frame composer
> in the HDMI block is working, but it's not producing any sync signals or
> pixel data.