It was hard to describe whats going on so I recorded it.
I am trying to get windows 10 running on my TV through a VSX 531 receiver with 4k + HDR enabled.
Its a Windows 10 with AMD RX550 -> Pioneer VSX 531 -> Samsung KU7000 TV
When Connecting directly to the TV everything works with HDR and 10bit color space is selectable and working. I get the following info in dxdiag when connecting the RX550 directly to the TV and everything works fine.
Current Mode: 3840 x 2160 (32 bit) (60Hz)
HDR Support: Supported
Display Topology: Internal
Display Color Space: DXGI_COLOR_SPACE_RGB_FULL_G2084_NONE_P2020
Color Primaries: Red(0.659680,0.340344), Green(0.244641,0.670422), Blue(0.130383,0.040539), White Point(0.313000,0.329602)
Display Luminance: Min Luminance = 0.010000, Max Luminance = 1499.000000, MaxFullFrameLuminance = 799.000000
Monitor Name: Generic PnP Monitor
Monitor Model: SAMSUNG
Monitor Id: SAM0D3B
Native Mode: 3840 x 2160(p) (60.000Hz)
Output Type: HDMI
Monitor Advanced Color Capabilities: BT2020RGB BT2020YCC Eotf2084Supported AdvancedColorSupported AdvancedColorEnabled
Display Pixel Format: DISPLAYCONFIG_PIXELFORMAT_NONGDI
It is when I put the receiver in the middle it fails as shown in the video, The specs does say the receiver supports HDCP 2.2 and Ultra HD (4K/60p/4:4:4) passthrough.
https://www.pioneerelectronics.com/PUSA/Home/AV-Receivers/Pioneer+Receivers/VSX-531
BUT when I turn off HDR settings on the TV A 4k picture works through the receiver but with HDR disabled so I get the following info in dxdiag.
Card name: Radeon RX 550 Series
Current Mode: 3840 x 2160 (32 bit) (60Hz)
HDR Support: Not Supported
Display Topology: Internal
Display Color Space: DXGI_COLOR_SPACE_RGB_FULL_G22_NONE_P709
Color Primaries: Red(0.641125,0.330578), Green(0.301281,0.601086), Blue(0.150891,0.061047), White Point(0.280773,0.290539)
Display Luminance: Min Luminance = 0.500000, Max Luminance = 270.000000, MaxFullFrameLuminance = 270.000000
Monitor Name: Generic PnP Monitor
Monitor Model: VSX-531
Monitor Id: PIO1037
Native Mode: 3840 x 2160(p) (30.000Hz)
Output Type: HDMI
Monitor Advanced Color Capabilities: Eotf2084Supported
Display Pixel Format: DISPLAYCONFIG_PIXELFORMAT_32BPP
I am thinking the problem is a HDCP handshake with the receiver when HDR is enabled on TV or the receiver is not fully 4k HDR passthrough compliant as advertised. I don't know if I should get a HDCP 2.2 stripper or just replace the receiver ?
