Success with a raw LCD interface, but what about color space?

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I have a 100% success connecting a 640x480 raw LCD panel via 1.8V to
3.3V level shifters using rev C board.
One remaining issue is that the video driver is using 24 bit color for
output since that is what the DVI connected display wants. My panel is
18 bits. I could rewire the video output bits in hardware 24 to 18
leaving some unconnected, but it's wasteful: I'd rather have extra i/o
lines on the J4/J5 connectors.

I can brute force OMAP video registers by using the regrw.ko driver
and then I can get proper 18 bit mapping, but this is ugly.

Is there an "official" way to switch the video driver to 18 bits? I
couldn't find any such parameter.
The 16 or 32 or whatever after resolution is NOT the same thing. The
depth of the frame buffer doesn't have to match the output.

Thanks.

2

One remaining issue is that the video driver is using 24 bit color for
output since that is what the DVI connected display wants. My panel is
18 bits. I could rewire the video output bits in hardware 24 to 18
leaving some unconnected, but it's wasteful: I'd rather have extra i/o
lines on the J4/J5 connectors.

Is there an "official" way to switch the video driver to 18 bits?

Hi Alex,

I don't know if there is any official way to handle 18-bit, but in order to
move fast forward, I would just stay at 24-bit and do the rewiring as
suggested. In order to use the last 6 pins as GPIOs just change the
pin-muxing to GPIO-mode instead of the current DSS-mode and everything will
work out just fine. The DSS/DISPC module won't know that some of its signals
aren’t connected to any balls and you will be able to use the balls as
GPIOs... :slight_smile:

Best regards - Good luck
  Søren