We see dull colours on our LCD, using "modetest" on our custom board, while the colours are bright when the same LCD hangs on the DK2. Are there possible causes we could check? Colour space, gamma correction?
We have made a custom board with an STM32MP157CAD MPU, this board is very similar to the DK2. We have adapted an LCD driver to support our LCD screen, over the DSI interface. It works, both on the DK2 with our own LCD screen, and on our custom board with the same LCD screen, but on our custom board, the colours are less bright than on the DK2. We have already checked: the kernel is the same, the driver is the same, the voltage backlight is the same.
Is there some reason why our LCD is duller? Possibly a wrong colour space or gamma correction, but where are those specified? We use neither Wayland nor X11, we use the "modetest" test program to show the SMPTE test pattern, as explained on <https://wiki.st.com/stm32mpu/wiki/DRM_KMS_overview#modetest_-28DRM-2FKMS_test_tool-29>, with a "modetest -M stm -s 29@32:480x800-60" command.