Imx6ull Overlay Framebuffer with Alpha Blending

[henri_koch]

Hello,

I am trying to enable the alpha blending capability as stated in the imx6ull reference manual to perform overlay on the main framebuffer. As so, I have my framebuffer buffer fb0 correctly set to ARGB32 format inside the mxsfb.c driver for a display (320x240x32) sending data over a 8 bits bus-width interface.

I configured the alpha blending hardware register to my need (set correct format to argb32, alpha_ctrl to embedded, ... ) and the framebuffer fb1 initialized is also in the correct format and size (320x240x32).

I understood that I need to unblank the fb1 framebuffer to activate the overlay but insteed of running properly, the screen starts to indicate random black and white line before the whole system stop working.

I also checked the register configuration using the memtool and everything seems to be fine. The same is happening if activate the AS_ENABLE register directly from this tool.

1. Any thought about the problem that I am facing ?
2. Is the ELCDIF AS register independent from PXP register ? I am not using the PXP right know.

Thank you !

[karangajjar]

Hi Henri Koch,

Can you please let us know what you want to do?

Like you have one application running on fb0 and you want to run other application on top of that i.e. fb1?

Or you want to display some text over a running application?

Can you please check below thread if it solves your query?

https://community.nxp.com/thread/440053 

Regards,

Karan Gajjar

[henri_koch]

Hi karan.gajjar@volansystech.com‌,

Thank you for your reply but the thread you linked do not provide answers to my problem.

I have a video stream running on fb0 and I want to overlay some information using fb1 (shapes and text) using the hardware overlay capability (32.4.10 Alpha Blending Interface) in the imx6ul datasheet and initialized in mxsfb.c video driver.

So yes, basically it is to display a video stream (fb0) with some shapes and text over it (fb1).

Thanks.

Best,

Henri

[igorpadykov]

Hi Henri

some alpha blending examples can be found in

pxp_v4l2_test\test - imx-test - i.MX Driver Test Application Software 

pxp_lib_test\test - imx-test - i.MX Driver Test Application Software 

Best regards
igor
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[karangajjar]

Hi Henri Koch,

We hope below link will help you along with the link shared by Igor:

i.MX6: Alpha blending example code 

Regards,

Karan Gajjar