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Usage of hdmi_group=0 in config.txt

Posted: Thu Mar 14, 2019 5:17 am
by leelabks
I have a display module with custom display timing (not the standard DMT or CEA) and i would like to use the "hdmi_group=0" in the "config.txt" to let the Raspberry Pi to do the "Auto-detect from EDID" which the EDID information is resided in the display module. However, it seems like the "hdmi_group=0" is not working this way. Has anybody successfully use "hdmi_group=0"("Auto-detect from EDID") in the "config.txt"?

"hdmi_group=0" information of "Auto-detect from EDID" from:
https://www.raspberrypi.org/documentati ... t/video.md

Re: Usage of hdmi_group=0 in config.txt

Posted: Thu Mar 14, 2019 6:07 am
by rpdom
hdmi_group=0 is the default if nothing is set in config.txt. You shouldn't need to set it manually.

If your display has non-standard settings it may not be possible for the Pi to configure it using just the EDID data. It may require you to set a custom mode.

Re: Usage of hdmi_group=0 in config.txt

Posted: Thu Mar 14, 2019 10:22 am
by 6by9
https://github.com/raspberrypi/firmware/issues/1121

Whilst it may seem easy to post on both the forums and raise an issue, if you don't at least acknowledge that you've done it then you'll get two independent conversations and people duplicating effort.

Re: Usage of hdmi_group=0 in config.txt

Posted: Thu Mar 14, 2019 6:01 pm
by aBUGSworstnightmare
My recommendation is to ignore the screens EDID and use a custom timing ; sure, you need to have the display spec. in your hands when doing this.
Note: never ever used group 0 for timings!

BTW: what is your hdmi_mode setting?

Or, read the EDID data from your screen and add a hdmi_timings line (together with hdmi_group=2 and hdmi_mode=87)

Re: Usage of hdmi_group=0 in config.txt

Posted: Sun Mar 17, 2019 11:29 am
by leelabks
yes, i am trying to gather different opinion from different perspective, for the discussion, please refer to: https://github.com/raspberrypi/firmware/issues/1121
Apology if i have made the trouble for anyone ...

Re: Usage of hdmi_group=0 in config.txt

Posted: Sun Mar 17, 2019 11:36 am
by leelabks
If i use the following custom timing then the display is ok

hdmi_group=2
hdmi_mode=87
hdmi_timings=720 0 80 10 150 1280 0 20 10 20 0 0 0 60 0 76000000 3

I just trying to see if there is any possibilities to let the Raspberry Pi to auto-detect the display timing setting like the Windows 7 system.