Vega 56 failing to process EDID from VR Headset

[James Dutton]

Hi,

I have an Oculus Rift S, that I am trying to get working in Linux.
I have an AMD Vega 56  graphics card.

The VR headset plugs into a display port of the Vega56.
The amdgpu driver sees the connection, and tries to process it.
The problem is it cannot process the EDID, so fails to recognise the
VR headset, and the VR headset does not work as a result.
Please find the EDID below.
I am guessing that the following is causing the problem:
Established Timings I & II: none
Standard Timings: none
Forcing the driver to understand the Detailed mode, to which it is failing.
If it helps, when attached to windows 10, it uses 1440x2560, portrait mode.
Some dmesg lines that may be useful:
// We should pick 1440x2560 as Windows picks that, but for some reason
is rejects it with error 10.
[10402.650734] [drm:create_validate_stream_for_sink [amdgpu]] Mode
1440x2560 (clk 571570) failed DC validation with error 10 (No DP link
bandwidth)
[10402.650991] [drm:update_stream_scaling_settings [amdgpu]]
Destination Rectangle x:0  y:0  width:1440  height:2560
[10402.651225] [drm:create_validate_stream_for_sink [amdgpu]] Mode
1440x2560 (clk 571570) failed DC validation with error 10 (No DP link
bandwidth)


Can anyone help give me with some pointers as to how to get the amdgpu
driver to accept this EDID?

edid-decode (hex):

00 ff ff ff ff ff ff 00 3e d2 12 00 00 00 00 00
01 1d 01 04 a5 00 00 00 0e 00 00 00 00 00 00 00
00 00 00 00 00 00 01 01 01 01 01 01 01 01 01 01
01 01 01 01 01 01 45 df a0 38 51 00 ee a5 d2 0c
f1 0c 00 00 00 00 00 10 00 00 00 ff 00 31 57 4d
47 48 35 32 30 47 41 39 35 32 00 00 00 fc 00 52
69 66 74 20 53 0a 20 20 20 20 20 20 00 00 00 10
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 33

----------------

EDID version: 1.4
Manufacturer: OVR Model 18 Serial Number 0
Made in week 1 of 2019
Digital display
8 bits per primary color channel
DisplayPort interface
Image size is variable
Gamma: 1.00
Supported color formats: RGB 4:4:4, YCrCb 4:4:4
Default (sRGB) color space is primary color space
First detailed timing includes the native pixel format and preferred
refresh rate
Color Characteristics
  Red:   0.0000, 0.0000
  Green: 0.0000, 0.0000
  Blue:  0.0000, 0.0000
  White: 0.0000, 0.0000
Established Timings I & II: none
Standard Timings: none
Detailed mode: Clock 571.570 MHz, digital composite
               1440 1650 1662 1752 (210  12  90)
               2560 2623 2624 4078 ( 63   1 1454)
               -hsync
               VertFreq: 80.000 Hz, HorFreq: 326.239 kHz
Display Product Serial Number: 1WMGH520GA952
Display Product Name: Rift S
Dummy Descriptor
Checksum: 0x33