Where is a config.txt of rpi in yocto linux

Technical Support
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1

Hello,

Since I have to use our new display with Apalis + Ixora board setting,

I have to change hdmi configuration as below.

hdmi_group=2
hdmi_mode=87
hdmi_timings=1920 0 0 2 126 720 0 2 2 4 0 0 0 60 0 89456640 8

It is easily changeable with Raspberry PI board in boot/config.txt, but I don’t know how to change in case of imx6 Apalis.

Is there anyone who could give me a clue to move forward?

Thanks in advance.

2

Unfortunately, such Raspberry PI proprietary way of configuring display parameters is not available on any other Embedded Linux based board. However, on our board you may do such configuration via device tree as explained in the following thread. More information may also be found on our developer website.

3

Thank you for your reply.

Can I ask one more thing? I want to change HDMI_timings with fbset, but I don’t know how to set up…

With Desktop, it says only 0 0 0 0 0 0 0 0 in timing data of fbset in targeted display.

How can I get exact value for fbset -t setup?

4

Thank you for your reply.

You are very welcome.

Can I ask one more thing?

Sure, go ahead.

I want to change HDMI_timings with fbset, but I don’t know how to set up…

Hm, sorry. I’m not quite sure what exactly it is that you are trying to achieve.

With Desktop, it says only 0 0 0 0 0 0 0 0 in timing data of fbset in targeted display.

What exactly do you mean by Desktop?

How can I get exact value for fbset -t setup?

Hm, I don’t recall ever having tried that. Can you elaborate on the exact software versions of things you are talking about?

5

So, what I am trying to do is set HDMI timing such as pixel_freq or framerate.

Therefore, I decide to use fbset, but since I don’t know exact pixel_freq or clock and other options to setup, I have tried to get the HDMI setup data from Ubuntu desktop which interfaces well with target display. However, when I type fbset in Ubuntu, it only says 0 0 0 0 0 0 0 0 in timing data which doesn’t help at all

6

More update,

I used below commands to setup, but

fbset -g 1920 720 1920 720 32 -t 89456640 0 0 0 0 16 2 -hsync low -vsync low

and the result is like this.

imx-ipuv3 2400000.ipu: WARNING: try to adapt timming, but failed
imx-ipuv3 2400000.ipu: WARNING: adapt panel end blank lines
mxc_sdc_fb fb@0: timeout when waiting for flip irq
mxc_sdc_fb fb@0: timeout when waiting for flip irq
mxc_sdc_fb fb@0: timeout when waiting for flip irq

7

I’m still missing the information on what exact software versions of things you are talking about. Plus what exotic HDMI screen is it that you are trying to connect? As per HDMI specification such configuration is usually done automatically via DDC/EDID. What is it that convinced you that you shall do it differently?