White veil on HDMI display + HDMI stops

[pinkpr]

Hello,

I'm currently working on an iMX6DL based board. We are using an HDMI display to show a Qt application.

I sometimes have a problem where the image is displayed, but there's a kind of "white veil" on it. I mean, it looks like the gamma parameter had been set to a very higher value. It stays as it is until I manually reboot the display, which I think lead to a reset of the HDMI output. When I dump the framebuffer, everything looks normal on the image I get, so I'm pretty sure that the problem does not come from the framebuffer itself.

Otherwise, I sometimes have an other problem when I run or stop a Qt app : the screen completely stops working and pixels are slowly fading to white. It looks exactly like when I blank the framebuffer, but I didnt. Also, the framebuffer / hdmi logs in dmesg don't show any framebuffer blanking. That's why I think it's most probably the HDMI that stops operating.

Do you guys have any idea of what is causing those 2 problems ?

Regards,

[igorpadykov]

Hi Pierre-Olivier

one can try to check if this problem is caused by poor signal or signal noise,

making shorter cables and possibly using more quality shielding cables.

Best regards
igor
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[pinkpr]

The display actually is a MIPI DSI display behind a HDMI --> MIPI converter.

I just made some tests, and the actual problem comes from the DSI display itself. Then it has nothing to do with the iMX HDMI output ...