[meta-fsl-arm] Sabre* and HDMI

[Gary Thomas <gary@mlbassoc.com>]

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Disclaimer - this question is not 100% BSP, but I'm hoping
someone reading it might have some insights.

I have multiple i.MX6 boards which I support using Poky/Yocto
plus meta-fsl-arm*.  The problem I'm looking at is on some
of them, HDMI works correctly where on others the screen is
clipped (overscan).

On the SabreLite, using linux-boundary_3.10.53, HDMI works
correctly (on all the monitors I have tried).  An image of
the upper left of the screen is in HDMI-OK.png

On SabreSD, using linux-imx_3.10.53, HDMI on a 720p monitor,
the image is clipped with upwards of 5% of the pixels missing.
This is shown in HDMI-BAD.png

I've not yet tried the linux-boundary kernel on the SabreSD,
but I expect the same result as I have seen this problem on
other boards (internal) that use the linux-boundary kernel.

Any insights on what might cause this?  About the only thing
we can think of is the SabreSD sends its HDMI signals through
a level-shifting ESD device whereas the SabreLite manages these
signals more directly using FETs and discrete circuitry.

Thanks for any ideas

-- 
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Gary Thomas                 |  Consulting for the
MLB Associates              |    Embedded world
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