I have a few questions about the R1811 board.
1)
With the original firmware, it supports single cable HBR3 connection for 5K 60Hz RGB. DSC is supported and DSC is enabled in Catalina.
Without DSC, only 8bpc can be supported. With DSC, does it support 5K 60Hz 10 bpc RGB? To find out, I would like to see an AGDCDiagnose of a 5K 60Hz single cable connection in Catalina.
2)
In Big Sur, DSC is usually disabled. But maybe DSC can be enabled. Try adding the following (taken from XDR override) to the override file:
Does it make a difference in Big Sur? Show an AGDCDiagnose output for this test.
3)
You might want to use dual cable connection which can do 10bpc using two HBR2 connections. You might want to do this if you can't enable DSC (because your GPU doesn't support DSC or maybe you don't trust DSC quality since visually lossless is not exactly lossless).
To do dual cable HBR2 connection, you need a different firmware. Does that firmware still allow a single cable connection for 5K 60Hz? Does it still support DSC?
I would like to see some AGDCDiagnose outputs for this as well (especially in Catalina which enables DSC by default when it's available).
I wonder if macOS can do dual cable for 10bpc and single cable for 8bpc for 5K? There's no way to force 8bpc in macOS though. 10bpc can be forced using HDR option.
We have seen (or at least one person reported) that the LG UltraFine 5K can do single cable 5K when the refresh rate is reduced to 39Hz (it is limited to HBR2 and pixel clock less than 600 MHz). But that shouldn't be required for the R1811 since it can support HBR3 link rate.
1)
With the original firmware, it supports single cable HBR3 connection for 5K 60Hz RGB. DSC is supported and DSC is enabled in Catalina.
Without DSC, only 8bpc can be supported. With DSC, does it support 5K 60Hz 10 bpc RGB? To find out, I would like to see an AGDCDiagnose of a 5K 60Hz single cable connection in Catalina.
2)
In Big Sur, DSC is usually disabled. But maybe DSC can be enabled. Try adding the following (taken from XDR override) to the override file:
Code:
<key>DisplayPort</key>
<dict>
<key>DisableDSC</key>
<integer>0</integer>
<key>DisableFEC</key>
<integer>0</integer>
</dict>3)
You might want to use dual cable connection which can do 10bpc using two HBR2 connections. You might want to do this if you can't enable DSC (because your GPU doesn't support DSC or maybe you don't trust DSC quality since visually lossless is not exactly lossless).
To do dual cable HBR2 connection, you need a different firmware. Does that firmware still allow a single cable connection for 5K 60Hz? Does it still support DSC?
I would like to see some AGDCDiagnose outputs for this as well (especially in Catalina which enables DSC by default when it's available).
I wonder if macOS can do dual cable for 10bpc and single cable for 8bpc for 5K? There's no way to force 8bpc in macOS though. 10bpc can be forced using HDR option.
We have seen (or at least one person reported) that the LG UltraFine 5K can do single cable 5K when the refresh rate is reduced to 39Hz (it is limited to HBR2 and pixel clock less than 600 MHz). But that shouldn't be required for the R1811 since it can support HBR3 link rate.
