Sony 4K TV only working as 1080 monitor

AdmiralJonB · 2021-05-29 00:05:02

I've got a Sony Bravia 4k TV that isn't detected as a 4k device under Arch. It is connected via a Displayport -> HDMI cable from an NVIDIA 2070 Super and using nvidia drivers. I have two other screens connected to the computer. It works fine on the same machine under Windows 10, so I doubt it's specifically a hardware issue.

When running xrandr, it comes through as the following:

DP-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 952mm x 535mm
   1920x1080     60.00*+  59.94    50.00    29.97    23.98
   1680x1050     59.95
   1600x900      60.00
   1280x1024     60.02
   1280x720      60.00    59.94    50.00    29.97    23.98
   1152x864      75.00
   1024x768      60.00
   800x600       60.32
   720x576       50.00
   720x480       59.94
   640x480       59.94    59.93

I've taken the edid and put it in edidreader.com, it appears to identify correctly and show the 4k resolutions under Block 1 -> Extension Header -> CEA Data Block -> Video Data Block (although it says they're not native, although that's the same for every resolution). I'll be honest, I don't know much about edids and whether it's useful or not, I was just following random stuff to try and find out more information.

I tried specifying an xorg config file for it, with a modeline generated by `cvt 3840 2160 30` and specifying in an xorg config (although I don't know if this would work if xrandr can't see the information). I don't know very much about xorg configs though - pretty much all I've ever done is use it to specify to use nvidia driver by default on some machines that don't automatically do so.

Section "Monitor"
    Identifier "DP-1"
    Modeline "3840x2160_30.00"  338.75  3840 4080 4488 5136  2160 2163 2168 2200 -hsync +vsync
    Option "PreferredMode" "3840x2160_30.00"
EndSection

I don't know if that could be possible if xrandr doesn't pick up the information though.

I'm at the end of all of my knowledge here - I would really appreciate some help in diagnosing and potentially solving this issue, if it is solvable. Thanks for your time.

seth · 2021-05-29 06:39:27

https://wiki.archlinux.org/title/Xrandr … esolutions
If you struggle w/ your resolution,

% cvt12 3840 2160 30 -b
# 3840x2160 @ 30.000 Hz Reduced Blank (CVT) field rate 30.000 Hz; hsync: 65.730 kHz; pclk: 257.66 MHz
Modeline "3840x2160_30.00_rb2"  257.66  3840 3848 3880 3920  2160 2177 2185 2191 +hsync -vsync

That's still well above the FullHD pclk of 173.00 MHz but also much below 338.75 MHz

And please post your xorg log.

Also

Displayport -> HDMI cable

If the output has a DP inlet, please try using this.

AdmiralJonB · 2021-05-29 12:16:54

I've uploaded log and minimal config here: https://gitlab.com/-/snippets/2128064 (other than changing username and hostname). I also tried setting the xorg config file to use DFP-1 as that's what's appearing in the log to no effect.

I also tried using xrandr newmode/addmode, but that didn't work out so well:

jon@JonsArch ~ [1]> xrandr --newmode "3840x2160_30.00_rb2"  257.66  3840 3848 3880 3920  2160 2177 2185 2191 +
hsync -vsync
jon@JonsArch ~> xrandr --addmode DP-1 3840x2160_30.00_rb2
X Error of failed request:  BadMatch (invalid parameter attributes)
  Major opcode of failed request:  140 (RANDR)
  Minor opcode of failed request:  18 (RRAddOutputMode)
  Serial number of failed request:  45
  Current serial number in output stream:  46

The monitor doesn't have a DP inlet unfortunately. The HDMI from the GPU is reserved for a VR device and would prefer not to use it on a long-term basis for the TV, I'll see if I can find a long enough HDMI cable to test it but I'm not sure I have one.

Incidentally, I got the edid via the nvidia-settings application, which doesn't detect the resolution.

Last edited by AdmiralJonB (2021-05-29 12:21:05)

seth · 2021-05-29 16:11:16

[  6114.192] (--) NVIDIA(GPU-0): SONY TV  *00 (DFP-1): 165.0 MHz maximum pixel clock

This is a problem, 165MHz will allow you to run FullHD w/ 60HZ and reduced blanking or maybe w/o rb but not much more.

Option "ModeValidation" "NoMaxPClkCheck"

will allow you to ignore that but I do not necessarily consider that a good idea.

I'm putting all your money on the adapter now.

Arch Linux

#1 2021-05-29 00:05:02

Sony 4K TV only working as 1080 monitor

#2 2021-05-29 06:39:27

Re: Sony 4K TV only working as 1080 monitor

#3 2021-05-29 12:16:54

Re: Sony 4K TV only working as 1080 monitor

#4 2021-05-29 16:11:16

Re: Sony 4K TV only working as 1080 monitor

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