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Force HDMI 2.1 instead of 2.0 at low bandwith ? (CRU or other way)
11-19-2023, 03:41 AM (Last edited: 11-22-2023, 06:18 PM by Wolfi)
Post: #1
Force HDMI 2.1 instead of 2.0 at low bandwith ? (CRU or other way)
Is a way possible force HDMI 2.1 instead of 2.0 at low bandwith ?

Because if HDMI 2.0 bandwith is enough it use everytime HDMI 2.0, example at 3840x2160@60hz(8bit) or 3840x2160@23,976hz(12bit)
In HDMI 2.1 mode it use all time the same bandwith which is write in EDID, example 40gbit is use for 3840x2160@120hz(10bit) and also for 3840x2160@60hz(10bit)
The HDMI 2.1 40gbit connection is in use only if HDMI 2.0 is not enough.

I want use HDMI 2.1 also for example 3840x2160@23,976hz, because i have sometimes signal lost problem if switch HDMI 2.0 to 2.1, switching inside the bandwith from 2.1 are never problem or in use of 2.1 over long time (The problem is only in the switching moment, and it is not the cable, fibre cable have same problem)

I try remove the HDMI support in EDID extension block, but not work.
For 3840x2160@50hz/60hz is simple possible force HDMI 2.1 with 10bit, but for 23,976hz it is not enough, and it switch to HDMI 2.0, and i switch many times in 23,976hz for movies.


btw. import a EDID file (inf or dat) in cru, and export it without changes it result in other EDID code. (I test it on a original EDID file export from LG Oled CX)
This is allready know ?
I not know it have a influence ?

Very Thanks for this great tool CRU, i use it since +10 years and CRT times.
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11-20-2023, 05:44 AM
Post: #2
RE: Force HDMI 2.1 instead of 2.0 at low bandwith ? (CRU or other way)
I think the driver will always send anything up to 600 Mcsc character rate as TMDS for compatibility reasons. You can try reducing the TMDS character rate in the HDMI 2.x data block and see if it uses FRL instead, but the driver mignt not use that information.

CRU always sets certain values a certain way, so the exported data might have minor differences from the import. I want CRU 2.0 to be more complete and preserve everything in advanced mode (consolidated mode will probably rearrange things if any changes are made), but there are cases where the data can be nonsensical, which makes preserving everything more complicated to deal with.
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11-22-2023, 06:16 PM
Post: #3
RE: Force HDMI 2.1 instead of 2.0 at low bandwith ? (CRU or other way)
Good idea.
I have try 100, 20, 5mhz, in "HDMI 2.x support" or "HDMI support" or use both, or deactivate tmds clock, but it not change anything.
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