Altering screen resolution on the PCduino3

[KoNP]

So ARMbian is my preferred OS for the pcduino3 because it outperforms all of the other options. However, I'm having trouble altering the screen resolution. I'm trying to get it set to 1024x768@60p and it's not playing ball. I've edited script.bin and boot.cmd to change the display mode to output mode/type 4 (desired res and VGA mode respectively) but it just goes to a blank screen and refuses to boot when I reboot it.

 

What exactly do I need to do to get this resolution working? If 1024x768@60 isn't an option, I can work with 1280x1024@60 as well, but I'm still clueless as to the necessary steps to take to change it.

 

-edit-

 

Sorry I should add I'm using the jessie desktop legacy build.

[tkaiser]

Please have a look at http://linux-sunxi.org/Display

 

I would adjust boot.cmd to read 'disp.screen0_output_mode=EDID:1280x720p60', then re-create boot.scr and see whether that helps. With A20 legacy kernel you should be able to use EDID values if present and also set a 'special' (non supported) resolution from within /etc/rc.local with fbset

[KoNP]

Ok well, I've tried a few things and it always leads to the same thing onscreen: input signal out of range. I have to plugpull and reboot it every time.

 

Trying to change HDMI modes with a10disp leads to a message saying pretty much every resolution is reported by the driver as incompatible.

 

Oddly enough, the very first screen that appears on power-up correctly auto-sets to 1024*768. After it goes into Armbian though, it changes to 1920*1080. So obviously Armbian isn't "reading" the screen right.

 

How would I use fbset to add the unsupported resolution in the way you suggested?

[KoNP]

I just won. All I needed to do was add an edid flag to boot.scr

 

Works perfectly now.

[KoNP]

Argh ffs this is infuriating. I plugged in a hdmi-to-vga adapter and it immediately defaulted back to 1280*720. I updated script.bin with VGA mode and I'm back to booting to a black screen.

 

What the hell is going on? Why can't I get it to correctly output if I manually give it settings i know it can use?

[tkaiser]

I just won. All I needed to do was add an edid flag to boot.scr

 

Well, isn't this what I suggested when I wrote "I would adjust boot.cmd to read 'disp.screen0_output_mode=EDID:1280x720p60'"?

 

Argh ffs this is infuriating. I plugged in a hdmi-to-vga adapter and it immediately defaulted back to 1280*720. I updated script.bin with VGA mode and I'm back to booting to a black screen.

 

The A20 SoC used on your board does support both HDMI and VGA. The only boards that expose VGA are AFAIK the Cubietruck and some Olimex boards (where you need a special cable to get the signal from pin header to VGA connector). All other A20 boards are not able to use the SoC's VGA cabapilities. If you use a cheap HDMI to VGA adapter with your board and change settings in script.bin to output using VGA then

• your VGA screen is still connected to A20's HDMI output (through a converter though)
• the cheap HDMI-to-VGA adapter obviously is too dumb to generate proper EDID information from/for the connected VGA display
• by choosing VGA instead of HDMI you ensure that no display signal is available on the HDMI connector so your HDMI-to-VGA adapter has nothing to convert

Using a VGA monitor with your board will only work if the display has a known and supported resolution. But as already written: HDMI driver for A20 supports setting the resolution through fbset, so you do an 'apt-get install fbset', read the manual and check the available modes (4:3 displays should be supported out of the box)