Angstrom-qt5-x11-image - Enabling LVDS display during U-boot and kernel boot

Is there any way to enable the display (LVDS) during the u-boot and kernel boot sequences in the stock angstrom-qt5-x11-image OpenEmbedded image? The backlight seems to come on but there is no output on the display.

Greetings @kwebster83!

Can you please provide more information about the LVDS display you’re using?

Also, please check this community question that mentions LVDS configuration before booting. You might need to recompile U-Boot and the Linux kernel with the correct timings for your specific display.

@gustavo.tx

Well, I can tell you that is a 1024x600 display and that the lvds-single-channel.sh script which resides in /usr/bin makes it work.

I’m guessing that I’ll need to modify the various sources in the kernel and u-boot layers rather than it being just changes to the env variables, however as per the link you refer to, I believe the other user didn’t have any success with this.

@kwebster83,

Yes, you’ll probably need to tweak the display timings here - be sure to check if you’re in the correct U-Boot branch corresponding to the U-Boot version running on your board. You’ll need to do the same to the device tree in the kernel.

It looks like the user in the question was able to get the U-Boot output but failed to get the kernel output. This will depend a lot on the LVDS transceiver/display used, so it is worth it to give it a try.

I’ve not really progressed this very much due to other priorities, however, as I’m using an Apalis T30 and 2.8.7b of the kernel, there is no device tree to speak of.

I just need to be able to display a splash screen to indicate to the end user that something is happening/loading whereas at the moment, for 15 seconds, there’s just nothing.

Can’t you just use gpio commands in U-Boot to make it work?

@marcel.tx Please can you elaborate further? How do you mean?

@kwebster83 , please see if the solution of this similar problem may suit you: