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Display bpp definition on device-tree

Question asked by Nuno Vilaça on Apr 20, 2015
Latest reply on Oct 28, 2015 by Nuno Vilaça

Hi.

We are building a board using Variscite's Var-som-mx6 module, and we are having trouble to set the lvds's bpp to 24 on the device-tree files.

 

Display are working well, we got timings correct, data-with to 24, etc but the default bpp remains at 16 (we can check it visually by send images to the FB that use colour gradients, but also confirm it by making a cat to /sys/class/grafics/fbX/bits_per_pixel. )

 

I managed to set it using u-boot's kernel parameters (video=mxcfb0:dev=ldb,800x600M@59,if=RGB24,bpp=24), but i really would really like to achieve the same using the device-tree files. Is it possible?

 

i already tried adding diferent properties to the framebuffer:
mxcfb2: fb@1 {
compatible = "fsl,mxc_sdc_fb";
disp_dev = "ldb";
interface_pix_fmt = "RGB24";
default_bpp = <24>;
bpp = <24>;
int_clk = <0>;
late_init = <0>;
status = "disabled";
};

 

and even trying to set them together with the display timmings:

display-timings {
native-mode = <&timing1>;
timing1: hsd100pxn1 {
clock-frequency = <40000000>;
hactive = <800>;
vactive = <600>;
hback-porch = <88>;
hfront-porch = <40>;
vback-porch = <23>;
vfront-porch = <39>;
hsync-len = <128>;
vsync-len = <4>;
bpp = <24>;
};
};

 

We use 2 identical lvds displays, using both channels, so i set the device on channel 0 using u-boot, and am trying to acieve the same on channel 1 using dtb only.

 

Using kernel 3.10.31

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