You are not logged in.

#1 2021-11-21 17:37:25

Sapiens
Member
Registered: 2021-07-05
Posts: 39

[solved] Unable to set desired refresh rate!

Hi there,

I bought a new display a few days ago. It supports 4K, 120Hz via HDMI 2.1, 144Hz via Display Port 1.4,
The card in my computer is a AMD RX 550 with HDMI 2.0 and Display Port 1.4, I am using the open  source xf86-video-amdgpu driver and have connected the display via DisplayPort.

[sapiens@computer ~]$ xrandr -q
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DisplayPort-0 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     60.00*+  60.00    59.94  
   2560x1440    143.86   119.88    59.94  
   1920x1080    143.85   120.00   119.88    60.00    60.00    59.94  
   1680x1050     59.95  
   1280x1024     60.02  
   1440x900      59.89  
   1280x720     120.00   100.00   119.88    60.00    50.00    59.94  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94  
HDMI-A-0 disconnected (normal left inverted right x axis y axis)
DVI-D-0 disconnected (normal left inverted right x axis y axis)
[sapiens@computer ~]$ 

As you can see xrandr only recognizes the display to be 4K/60Hz capable.

I tried the following:

[sapiens@computer ~]$ cvt 3840 2160 144
# 3840x2160 143.94 Hz (CVT) hsync: 338.25 kHz; pclk: 1829.25 MHz
Modeline "3840x2160_144.00"  1829.25  3840 4200 4624 5408  2160 2163 2168 2350 -hsync +vsync
[sapiens@computer ~]$ xrandr --newmode "3840x2160_144.00"  1829.25  3840 4200 4624 5408  2160 2163 2168 2350 -hsync +vsync
[sapiens@computer ~]$ xrandr --addmode DisplayPort-0 3840x2160_144.00
[sapiens@computer ~]$ xrandr -q
Screen 0: minimum 320 x 200, current 3840 x 2160, maximum 16384 x 16384
DisplayPort-0 connected primary 3840x2160+0+0 (normal left inverted right x axis y axis) 697mm x 392mm
   3840x2160     60.00*+  60.00    59.94  
   2560x1440    143.86   119.88    59.94  
   1920x1080    143.85   120.00   119.88    60.00    60.00    59.94  
   1680x1050     59.95  
   1280x1024     60.02  
   1440x900      59.89  
   1280x720     120.00   100.00   119.88    60.00    50.00    59.94  
   1024x768      75.03    60.00  
   800x600       75.00    60.32  
   720x576       50.00  
   720x480       60.00    59.94  
   640x480       75.00    60.00    59.94  
   3840x2160_144.00 143.94 
[sapiens@computer ~]$ xrandr -v --output DisplayPort-0 --mode 3840x2160_144.00
xrandr program version       1.5.1
xrandr: Configure crtc 0 failed

I hope this gives some indication to anyone what might be wrong, since my searched lead me no further than this. Any help is appreciated.

Last edited by Sapiens (2021-11-24 20:45:02)

Offline

#2 2021-11-21 17:42:51

Slithery
Forum Moderator
From: Norfolk, UK
Registered: 2013-12-01
Posts: 4,753

Re: [solved] Unable to set desired refresh rate!

Does your cable support that resolution?


No, it didn't "fix" anything. It just shifted the brokeness one space to the right. - jasonwryan
Closing -- for deletion; Banning -- for muppetry. - jasonwryan

aur - dotfiles

Offline

#3 2021-11-21 19:07:01

Sapiens
Member
Registered: 2021-07-05
Posts: 39

Re: [solved] Unable to set desired refresh rate!

Slithery wrote:

Does your cable support that resolution?

I only have two DisplayPort cables, one came with the monitor. Just to make sure I have ordered an additional cable from Club3D. Those are supposed to be high quality.

Last edited by Sapiens (2021-11-21 19:41:30)

Offline

#4 2021-11-21 21:00:12

seth
Member
Registered: 2012-09-03
Posts: 25,086

Re: [solved] Unable to set desired refresh rate!

Please identify the output (vendor/model), post your xorg log, https://wiki.archlinux.org/title/Xorg#General and try

% cvt12 3840 2160 144 -b
# 3840x2160 @ 144.000 Hz Reduced Blank (CVT) field rate 144.000 Hz; hsync: 333.216 kHz; pclk: 1306.21 MHz
Modeline "3840x2160_144.00_rb2"  1306.21  3840 3848 3880 3920  2160 2300 2308 2314 +hsync -vsync

Offline

#5 2021-11-21 21:20:17

progandy
Member
Registered: 2012-05-17
Posts: 4,638

Re: [solved] Unable to set desired refresh rate!

seth wrote:
% cvt12 3840 2160 144 -b

4k/144 is not possible with this graphics card.

DP1.4 (HBR3) is just enough to run the reduced blanking v2 modeline for 4k/120hz.
HDMI 2.0 is at the limit with 1440p/144hz or 4k/70hz at maximum reduced blanking

Limits checked with
https://tomverbeure.github.io/video_timings_calculator

4k/120 created with cvt12:

$ cvt12 3840 2160 120 -b
# 3840x2160 @ 120.000 Hz Reduced Blank (CVT) field rate 120.000 Hz; hsync: 274.440 kHz; pclk: 1075.80 MHz
Modeline "3840x2160_120.00_rb2"  1075.80  3840 3848 3880 3920  2160 2273 2281 2287 +hsync -vsync

Last edited by progandy (2021-11-21 21:24:19)


| alias CUTF='LANG=en_XX.UTF-8@POSIX ' |

Offline

#6 2021-11-21 22:34:41

Sapiens
Member
Registered: 2021-07-05
Posts: 39

Re: [solved] Unable to set desired refresh rate!

seth wrote:

Please identify the output (vendor/model) [...]

GPU: PowerColor Radeon RX 550 Red Dragon V3, 2GB GDDR5, DVI, HDMI, DP (AXRX 550 2GBD5-DHA/OC)
Screen: Gigabyte Aorus FV43U

seth wrote:

[...] post your xorg log,

https://termbin.com/8sg2

progandy wrote:

4k/144 is not possible with this graphics card.

Display Stream Compression is not working on Linux?

progandy wrote:

4k/120 created with cvt12:

$ cvt12 3840 2160 120 -b
# 3840x2160 @ 120.000 Hz Reduced Blank (CVT) field rate 120.000 Hz; hsync: 274.440 kHz; pclk: 1075.80 MHz
Modeline "3840x2160_120.00_rb2"  1075.80  3840 3848 3880 3920  2160 2273 2281 2287 +hsync -vsync
[sapiens@computer ~]$ xrandr --newmode "3840x2160_120.00_rb2"  1075.80  3840 3848 3880 3920  2160 2273 2281 2287 +hsync -vsync
[sapiens@computer ~]$ xrandr --addmode DisplayPort-0 3840x2160_120.00_rb2
[sapiens@computer ~]$ xrandr -v --output DisplayPort-0 --mode 3840x2160_120.00_rb2
xrandr program version       1.5.1
xrandr: Configure crtc 0 failed

Last edited by Sapiens (2021-11-21 22:44:54)

Offline

#7 2021-11-21 22:53:51

progandy
Member
Registered: 2012-05-17
Posts: 4,638

Re: [solved] Unable to set desired refresh rate!

Sapiens wrote:

Display Stream Compression is not working on Linux?

Right, that exists as well. As far as I know, AMD RX 550 would be too old for that, though. Only Navi and newer have it I think.

Last edited by progandy (2021-11-21 22:56:41)


| alias CUTF='LANG=en_XX.UTF-8@POSIX ' |

Offline

#8 2021-11-22 08:20:27

seth
Member
Registered: 2012-09-03
Posts: 25,086

Re: [solved] Unable to set desired refresh rate!

Was added in 2019 https://lists.freedesktop.org/archives/ … 38759.html - but your GPU HW doesn't support it.
The monitor EDID reports the resolutions, but the driver filters them and apparently even on reduced blanking the 120Hz pclk is too high.

You can try https://wiki.archlinux.org/title/Variable_refresh_rate - the monitor supports it.

Offline

#9 2021-11-22 17:56:18

Sapiens
Member
Registered: 2021-07-05
Posts: 39

Re: [solved] Unable to set desired refresh rate!

The missing DSC is unfortunate. Still I made some progress. I was able to create a custom resolution with 4K/110Hz that I was able to apply! At least that is working for now and I should be able to live with it until the GPU prices might come down and I can buy a GPU that is either HDMI2.1 or DSC capable. I will receive another DP cable tomorrow and see if that changes anything. So thank you both for helping!

I have an additional question though. When I boot the computer I land in the terminal since I start my I3 desktop environment with the `startx`-command. However after the grub menu the display stays completely black. I have to enter my login credentials and run startx blindly. When I3 starts the screen starts to display again! Is there anything I can do to make it display the console properly?

Last edited by Sapiens (2021-11-22 17:57:59)

Offline

#10 2021-11-22 18:10:51

Slithery
Forum Moderator
From: Norfolk, UK
Registered: 2013-12-01
Posts: 4,753

Re: [solved] Unable to set desired refresh rate!


No, it didn't "fix" anything. It just shifted the brokeness one space to the right. - jasonwryan
Closing -- for deletion; Banning -- for muppetry. - jasonwryan

aur - dotfiles

Offline

#11 2021-11-22 18:38:12

progandy
Member
Registered: 2012-05-17
Posts: 4,638

Re: [solved] Unable to set desired refresh rate!

Here is a customized 4K/120Hz you could try. The calculator I linked shows it as utilizing 99% of DP HBR3.  (I shortened the vsync by 10 pixels, no idea if that will work for you)

Modeline "3840x2160_120.00_custom"  1071.101    3840 3848 3880 3920    2160 2263 2271 2277  +hsync -vsync

Last edited by progandy (2021-11-22 18:48:12)


| alias CUTF='LANG=en_XX.UTF-8@POSIX ' |

Offline

#12 2021-11-22 18:57:57

Sapiens
Member
Registered: 2021-07-05
Posts: 39

Re: [solved] Unable to set desired refresh rate!

This makes it worse. Not only does the screen turn off after Grub, now I am not even seeing the decryption password promt.

progandy wrote:

Here is a customized 4K/120Hz you could try. The calculator I linked shows it as utilizing 99% of DP HBR3.  (I shortened the vsync by 10 pixels, no idea if that will work for you)

Modeline "3840x2160_120.00_custom"  1071.101    3840 3848 3880 3920    2160 2263 2271 2277  +hsync -vsync

I can apply this mode! What does it mean that you shortened the vsync by10 pixels? I'm not sure what the implications are.

Last edited by Sapiens (2021-11-22 19:03:17)

Offline

#13 2021-11-22 19:10:29

progandy
Member
Registered: 2012-05-17
Posts: 4,638

Re: [solved] Unable to set desired refresh rate!

Sapiens wrote:

I can apply this mode! What does it mean that you shortened the vsync by10 pixels? I'm not sure what the implications are.

That shortens the time used to send the "vertical blanking" signal and reduces the bandwidth consumed by it. I was a bit more aggressive than the "reduced blanking v2" as defined by VESA. If you monitor likes the signal, then there should be no problem at all.
https://en.wikipedia.org/wiki/Coordinat … d_blanking

For your invisible boot, maybe try to force a lower resolution during boot: https://wiki.archlinux.org/title/Kernel … cing_modes or try to force your new modeline with a custom edid: https://github.com/akatrevorjay/edid-generator

Last edited by progandy (2021-11-22 19:25:02)


| alias CUTF='LANG=en_XX.UTF-8@POSIX ' |

Offline

#14 2021-11-24 20:44:22

Sapiens
Member
Registered: 2021-07-05
Posts: 39

Re: [solved] Unable to set desired refresh rate!

progandy wrote:

For your invisible boot, maybe try to force a lower resolution during boot: https://wiki.archlinux.org/title/Kernel … cing_modes

Forcing the resolution to FullHD@60Hz via kernel parameter worked and I am now able to see the console. Thank you, I will mark the thread as solved.

By the way, I also received a new high quality display port cable and the higher refresh rates are still unavailable without manually setting them.

Offline

#15 2021-11-24 20:54:13

seth
Member
Registered: 2012-09-03
Posts: 25,086

Re: [solved] Unable to set desired refresh rate!

The AMD RX 550 has "only" DP 1.4 support - using a DP 2.0 cable or one with golden plugs (sigh) won't change that.
The custom modelines you inject are not announced by the monitor EDID (what's not a surprise and normal and not a bug) and the more demanding ones that are announced, are filtered by the GPU because "can't do that, sorry".

Offline

#16 2021-11-27 22:35:29

Sapiens
Member
Registered: 2021-07-05
Posts: 39

Re: [solved] Unable to set desired refresh rate!

seth wrote:

The AMD RX 550 has "only" DP 1.4 support - using a DP 2.0 cable or one with golden plugs (sigh) won't change that.
The custom modelines you inject are not announced by the monitor EDID (what's not a surprise and normal and not a bug) and the more demanding ones that are announced, are filtered by the GPU because "can't do that, sorry".

On the quality of display port cables.

Offline

#17 2021-11-27 22:47:45

seth
Member
Registered: 2012-09-03
Posts: 25,086

Re: [solved] Unable to set desired refresh rate!

Like with anything in life there're good ones and bad ones, but again: this has nothing to do with the cable. The limiting factor is your GPU.

Offline

Board footer

Powered by FluxBB