How to adjust overscan for CRT? about emuelec

[25minutes]

Very nice article. Problem is resolved.

Thanks again SumavisionQ5 & shantigilbert. Merry Christmas! :)

[shantigilbert]

This is something that I have not investigated, I am pretty sure there is a command to do it, but I unfortunately do not know it.

I will try to search for a solution, but since I do not have a CRT I depend on other people to test it.

[25minutes]

Thanks shantigilbert. I can test it, just drop me a note when you have anything.

FYI. Below is the doc I used for Raspberry Pi (RetroPie). In addition to the parameters I mentioned earlier, it also requires overscan_scale=1, in order to make EmulationStation/RetroArch to obey the overscan settings.
https://retropie.org.uk/docs/Overscan/

[keeno1982]

I need it too. My TV have no point to point mode so can not work perfect on 1080P. Raspberry overscan setting is good for this.

[shantigilbert]

Sorry I can't find any info on this, I tried compiling fbset (full as the one included from busybox is very limited) but I still was not able to correct the overscan. I am out of ideas.

[25minutes]

Thank you very much for taking the time on investigating it. I truly appreciate that.

Since there's no easy solution, I close the ticket for now.

[shantigilbert]

Leave it open, hopefully someone could help :)

[SumavisionQ5]

The answer is alway there, in setres.sh! Read it carefully, and you will find an answer in 480cvbs or 576cvbs. I did not answer this issue becasue I hate someone might use EmuELEC for commerical purpose.

[25minutes]

Thanks SumavisionQ5. I have 2 questions:

1. I find a similar discussion at https://forum.odroid.com/viewtopic.php?f=112&t=17774&p=118897#p118897. The basic idea is to set /sys/class/graphics/fb0/window_axis & /sys/class/graphics/fb0/free_scale. It's for odroid c1, but the last post of the thread says it works on odroid c2 (which seems to be s905) as well.

However, When I test it on EmuELEC (S905M), it doesn't work. It turns out that I also have to set free_scale_axis, scale_width, scale_height. Do you know why?

2. I see both 480cvbs & 576cvbs use: fbset -fb /dev/fb0 -g 1280 960 1280 1920 $BPP. Does it have to be 1280x960? Can I use other values? Any tips for choosing these values? I'm asking because it's not really a common resolution.

[shantigilbert]

did this fix your issue?

[shantigilbert]

Yep that fixed the issue for me as well

@25minutes in my case I had to use these settings

	fbset -fb /dev/fb0 -g 1280 960 1280 1920 32
	echo 0 0 1279 959 > /sys/class/graphics/fb0/free_scale_axis
	echo 30 10 669 469 > /sys/class/graphics/fb0/window_axis
	echo 0x10001 > /sys/class/graphics/fb0/free_scale

so I am guessing the values depend on your monitor/tv/screen

[SumavisionQ5]

Thanks SumavisionQ5. I have 2 questions:

1. I find a similar discussion at https://forum.odroid.com/viewtopic.php?f=112&t=17774&p=118897#p118897. The basic idea is to set /sys/class/graphics/fb0/window_axis & /sys/class/graphics/fb0/free_scale. It's for odroid c1, but the last post of the thread says it works on odroid c2 (which seems to be s905) as well.

However, When I test it on EmuELEC (S905M), it doesn't work. It turns out that I also have to set free_scale_axis, scale_width, scale_height. Do you know why?

1. I see both 480cvbs & 576cvbs use: fbset -fb /dev/fb0 -g 1280 960 1280 1920 $BPP. Does it have to be 1280x960? Can I use other values? Any tips for choosing these values? I'm asking because it's not really a common resolution.

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