Why colibri-imx7-emmc_lxde-image-tezi_2.8b1 cannot change the display resolution?

Hi
Why colibri-imx7-emmc_lxde-image-tezi_2.8b1 cannot change the display resolution?
I use Toradex Easy Installer to install the OS image :colibri-imx7-emmc_lxde-image-tezi_2.8b1
After installed the video resolution default 640x480 then I modified to 1024x768 by:
Colibri iMX7 #env set vidargs video=mxsfb:1024x768M-16@60
Colibri iMX7 #env set videomode video=ctfb:x:1024,y:768,depth:18,pclk:39722,le:48,ri:16,up:33,lo:10,hs:96,vs:2,sync:0,vmode:0
Colibri iMX7 #saveenv
Colibri iMX7 #boot

But the display resolution still is 640x480.

I reinstall the “colibri-imx7-emmc_lxde-image-tezi_2.7-20180104” this is OK

Is this a bug for the new version v2.8b1?

Thanks

Yes this is a regression in 2.8b1. It will be fixed in 2.8b2.

However, using display timings from the device tree does work.

Thanks for your reply.
I am a new comer.
How to do using display timings from the device tree?
and I have built the image v.8b1 by using oe-core. How to modify the source code?
Thanks.

The Device Tree is part of the Linux kernel source code. I recommend to checkout the kernel sources separately. This process is explained in the Build U-Boot and Linux Kernel from Source Code article.

You can read more about device trees in the Device Tree Customization article.

In this case, you want to edit the lcdif node in the imx7-colibri-eval-v3.dtsi device tree.

You then can build the device tree (e.g. using make dtbs) and deploy it to the target as described in the above article. If you are satisfied with the results, you can create a patch file and add this to the Linux kernel recipe in OpenEmbedded (meta-toradex-nxp/recipes-kernel/linux/linux-toradex_4.9-1.0.x.bb, respectively in a own layer through bbappend).

I compared “imx7-colibri-eval-v3.dtsi” for iMX7D v2.7 and for IMX7D-eMMC v2.8b1
The 2 files is same.

see:

display0: lcd-display {
	    bits-per-pixel = <16>;
	    bus-width = <18>;

	    display-timings {
		    native-mode = <&timing_vga>;

		    /* Standard VGA timing */
		    timing_vga: 640x480 {
			    clock-frequency = <25175000>;
			    hactive = <640>;
			    vactive = <480>;
			    hback-porch = <40>;
			    hfront-porch = <24>;
			    vback-porch = <32>;
			    vfront-porch = <11>;
			    hsync-len = <96>;
			    vsync-len = <2>;

			    de-active = <1>;
			    hsync-active = <0>;
			    vsync-active = <0>;
			    pixelclk-active = <0>;
		    };

.......
 
		    /* Standard XGA timing */
		    timing_xga: 1024x768 {
			    clock-frequency = <65000000>;
			    hactive = <1024>;
			    vactive = <768>;
			    hback-porch = <160>;
			    hfront-porch = <24>;
			    vback-porch = <29>;
			    vfront-porch = <3>;
			    hsync-len = <136>;
			    vsync-len = <6>;

			    de-active = <1>;
			    hsync-active = <0>;
			    vsync-active = <0>;
			    pixelclk-active = <0>;
		    };
	    };
    };
};

Will change “native-mode = <&timing_vga>;” to “native-mode = <&timing_xga>;” for 1024x768?

How to create the patch file?

Thanks.

Yes. You can create a patchfile just by using git diff after doing the change.