iMX6 Local Alpha

[richogrady]

We are using local alpha (not in pixel but in a separate buffer) to combine a graphic plane and a video plane in kernel 4.1.15.  Everything works fine except whenever turning local alpha on or off via ioctl MXCFB_SET_LOC_ALPHA, the screen flashes. We tracked this down to mxc_ipuv3_fb.c where the ioctl is handled.  It seems this ioctl will always call the function mxcfb_set_par().  This function basically does a full reinit of fb0 and fb1 and causes the flashing. Turning global alpha on and off does not have such an issue.  Isn't there a cleaner way to turn on local alpha?

[b36401]

Here is an example for global alpha and local alpha:

https://community.nxp.com/thread/300324

Have a great day,
Victor

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