[meta-freescale] No HDMI video on imx6qsabresd with dizzy

Andreas Müller schnitzeltony at googlemail.com
Thu Nov 13 01:29:37 PST 2014

On Wed, Nov 12, 2014 at 11:58 PM, Nikolay Dimitrov <picmaster at mail.bg> wrote:
> Hi guys,
> I'm trying to use unmodified dizzy build with imx6q sabresd, for
> testing video playback. U-Boot outputs HDMI image during boot, but in
> Linux there's no HDMI image (no console, no video playback).
> The image is "fsl-image-multimedia-full", kernel 3.10.17. The device
> files /dev/video* and /dev/fb* are available, but gstreamer playback
> doesn't output any image on the HDMI port (seems to be stuck instead of
> playing).
> The kernel cmdline doesn't specify any video settings, which typically
> is an issue, but when I add the video bootargs:
> ...video=mxcfb0:dev=hdmi,1024x768M at 60,if=RGB24...
> The board stops to print any boot messages after "Starting kernel..."
> and seems to be stuck. Removing the video bootargs allows again to boot
> normally.
> I must admit that I'm somewhat puzzled by this behavior, as I already
> have daizy running with 3.10.17 on a custom board, and the video is
> working there with almost the same bootargs. Do you guys have any ideas
> for how to configure imx6q sabresd for HDMI video?
> Thanks in advance. Regards,
> Nikolay
> --
Had same here.

I think there are two problems:
* 3.10.17 EDID decoding works only for monitors with EDID extended
blocks (patch 0001..)
* 1024x768 is not a CEA mode. If I read the code of 3.10.17 correct,
HDMI supports only modes which are found in
drivers/video/mxc/mxc_edid.c const struct fb_videomode
mxc_cea_mode[64]. I hacked up working solution (patch 0002..). Note
that this is just a hack - it might lead to incorrect colour space
conversion or wrong PixelRepetitionOutput (see mxc_hdmi_setup:
hdmi->vic is always 0 for my patches).

These patches were tested with two monitors (1280x1024 / 1650x<I
forgot>) and seem to work fine.

Hope it wipes away your problem

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