24 bit LCD Display interfacing


we are using Colibri VF61 custom board interface with 800x480 TM070RBH10 LCD display.It is a 24 bit TFT LCD display. By default Colibri VF61 is in 18 bit resolution but we need to change in to 24 bit because some line are generate while using gradient type images.

We are change bit resolution through linux command xrand but that is not effective.

how i can able to change the bit resolution in Linux image.

NB: we are using Colibri_VF_LinuxImage V2.6 linux image with oecore

Thank you.

Hi Jojo

We are change bit resolution through linux command xrand but that is not effective.
What do you mean with that? What is your issue?

hi Jaski,

configure display property of colibri module through minicom terminal in Boot mode

So, you want to know how to change the display properties in u-boot?

hi jaski,

sorry,that was my mistake.
please tell me how to change 18 in to 24 bit resolution.

i want to know how to change 18 bit resolution into 24 bit in linux image

You need to differentiate between bus and framebuffer format. By default our BSP uses 18-bit bus interface and 16-bit frame buffers.

In order to make responsable use of the full 24-bit (RGB888) you should configure the framebuffer for 24-bit. You can change DefaultDepth in xorg.conf for the X-Server or through the kernel parameter fsl_dcu_drm.legacyfb_depth=24. See also Display Output, Resolution and Timings (Linux).

The display controller itself always outputs RGB888. On the unified display connector we only use the more significant bits of each color (e.g. SODIMM LDD<0-5> are B2 to B7). However, the device tree muxes all signals, so full 24-bit color should be available (see arch/arm/boot/dts/vf-colibri.dtsi). So if you connect your LCD to all 8-bit for each color, it will properly use full 24-bit colors.