Hi. I’m one of the folks that are playing with switching from Windows to Linux now that gaming has gotten to be feasible for so many major titles. I have used linux (including Fedora) on and off for years as part of my job. But I’m dealing with a problem well outside my area of expertise. My biggest issue is that I have no idea “where” the problem actually lies or where to start looking/asking for help. Do I talk to my monitor manufacturer? Graphics card vendor? Drm or Amd driver folks? So I’m starting here and hope someone can point me in the correct direction. I started my journey seeking advice on Reddit, and I’m now trying here.
The short version of my problem is that I have a Radeon 7800XT graphics card and a Samsung Odyssey G8 OLED (G80SD). Both the card and the monitor use and are connected via the DP2.1 cable that came with my monitor. But no matter what I do I can’t get the “Display Settings” in Linux to give me an option to select 240Hz on my monitor. The only options it presents are 30, 60, and 120 Hz. This exact same card, monitor, cable, port etc. has absolutely no issues if I boot to Windows. In the display settings for Windows 11 I immediately see 240Hz as an option, it works great in games as well.
Things I’ve Tried:
- Change DP ports on card: I’ve used every port no changes.
- Switch distro/DE: I’ve found the same issues with Mint, Ubuntu, Fedora, and Nobara. I’ve various Cinnamon, Gnome, and KDE versions of spins of different distros.
- Try a different graphics card. I borrowed an Radeon 7900 XTX after a redditor with the same monitor told me they didn’t have any issues on their 7900 XTX. Both cards have the same problem.
- Get “edid” from Windows and override the Linux edid. This recommendation came from a Arch Linux forum recommendation of a guy having a very similar issue with this same monitor. This was not an effective fix as the edids in both OSes were exactly the same.
- Make a modified edid that includes a 240Hz target. From the same user as #4 he ended up doing something to modify the edid to add a 240Hz target I got the file from him (found him on Reddit) and was not able to use it to give myself a similar option.
Thoughts and “clues”:
- edid-decode (pasted below) shows a “warning” that mentions 30-120Hz timings vs the monitor’s support of 48-240Hz. Seems like a massive hint. But I have no idea what to do with it. Maybe the Linux only looks for specific timing options from the edid but Windows reads the “monitor limits” and raises reasonable option within those limits?
Base EDID: Some timings are out of range of the Monitor Ranges:
Vertical Freq: 30.000 - 120.000 Hz (Monitor: 48.000 - 240.000 Hz)
- I am having this issue on DP2.1 but this sure looks like the exact problem that many have described as being related to HDMI 2.1. Is it possible that my graphic’s card DP2.1 port is actually somehow an HDMI signal that is being converted? And I’m hitting the known issue where AMD couldn’t release HDMI 2.1 support in the open source driver? If this is a thing is there a way to check this on cards? I’ve tried two graphics cards from two different manufacturers (Asrock and XFX).
- In a conversation with a Reddit user I was told “i discovered the root cause of the 240hz not working on linux btw. it was the displayid 2.0 section in the edid that had unknown data. it turns out that it was a displayid 2.1 block type that’s not implemented in the linux kernel, and that’s where the 240hz modes are stored (4k, 1440p, 1080p). i patched my kernel to implement the block type and the modes show up just fine without having to use modified edid firmware” the source of this quote was “another reddit user” so I have no idea if it’s real info or what the kernel patch for this would look like. I have not been able to find any public source that mentions this info so far.
System info:
7800x3d with x970e chipset
AsRock 7800 xt (and XFX 7900 xtx)
Fedora Linux 41 KDE Plasma (issue also present on Fedora 40)
“Debug” info:
xrandr out put does not show a 240Hz option
DP-3 connected primary 3840x2160+2880+0 (normal left inverted right x axis y axis) 697mm x 392mm
3840x2160 119.98*+
2048x1536 119.95
1920x1440 119.97
1600x1200 119.82
1440x1080 119.92
1400x1050 119.90
1280x1024 119.83
1280x960 119.89
1152x864 119.77
1024x768 119.80
800x600 119.85
640x480 119.52
320x240 117.34
2560x1600 119.93
1920x1200 119.90
1680x1050 119.89
1440x900 119.94
1280x800 119.85
1152x720 119.73
960x600 119.74
928x580 119.55
800x500 119.47
768x480 119.71
720x480 119.65
640x400 119.64
320x200 117.55
3200x1800 119.96
2880x1620 119.95
2560x1440 119.95
2048x1152 119.96
1920x1080 119.93
1600x900 119.95
1368x768 119.83
1280x720 119.86
1024x576 119.85
864x486 119.69
720x400 119.54
640x350 119.24
edid-decode
edid-decode (hex):
00 ff ff ff ff ff ff 00 4c 2d 35 e0 00 00 00 00
01 22 01 04 b5 46 27 78 3b 34 95 af 4e 3a bb 25
0c 50 54 25 cf 00 71 4f 81 c0 81 00 81 80 95 00
a9 c0 b3 00 d1 c0 4d d0 00 a0 f0 70 3e 80 30 20
35 00 b9 88 21 00 00 1a 00 00 00 fd 0c 30 f0 ff
ff ea 01 0a 20 20 20 20 20 20 00 00 00 fc 00 4f
64 79 73 73 65 79 20 47 38 30 53 44 00 00 00 ff
00 48 31 41 4b 35 30 30 30 30 30 0a 20 20 02 b3
02 03 3a f0 47 61 5f 10 3f 04 03 76 23 09 07 07
83 01 00 00 e3 05 c3 00 e6 06 05 01 60 4b 03 e5
01 8b 84 90 39 74 1a 00 00 03 07 30 f0 00 a0 60
02 4b 02 f0 00 00 00 00 00 00 56 5e 00 a0 a0 a0
29 50 30 20 35 00 b9 88 21 00 00 1a 6f c2 00 a0
a0 a0 55 50 30 20 35 00 b9 88 21 00 00 1a 02 3a
80 18 71 38 2d 40 58 2c 45 00 b9 88 21 00 00 1e
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 48
70 20 79 05 00 2a 00 12 01 ff 0e 6f 08 ef 01 ff
09 9f 05 ef 01 7f 07 37 04 ef 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 65 90
----------------
Block 0, Base EDID:
EDID Structure Version & Revision: 1.4
Vendor & Product Identification:
Manufacturer: SAM
Model: 57397
Made in: week 1 of 2024
Basic Display Parameters & Features:
Digital display
Bits per primary color channel: 10
DisplayPort interface
Maximum image size: 70 cm x 39 cm
Gamma: 2.20
DPMS levels: Off
Supported color formats: RGB 4:4:4, YCrCb 4:4:4, YCrCb 4:2:2
First detailed timing includes the native pixel format and preferred refresh rate
Display is continuous frequency
Color Characteristics:
Red : 0.6835, 0.3076
Green: 0.2275, 0.7304
Blue : 0.1464, 0.0478
White: 0.3134, 0.3291
Established Timings I & II:
DMT 0x04: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz
DMT 0x06: 640x480 75.000000 Hz 4:3 37.500 kHz 31.500000 MHz
DMT 0x09: 800x600 60.316541 Hz 4:3 37.879 kHz 40.000000 MHz
DMT 0x0a: 800x600 72.187572 Hz 4:3 48.077 kHz 50.000000 MHz
DMT 0x0b: 800x600 75.000000 Hz 4:3 46.875 kHz 49.500000 MHz
DMT 0x10: 1024x768 60.003840 Hz 4:3 48.363 kHz 65.000000 MHz
DMT 0x11: 1024x768 70.069359 Hz 4:3 56.476 kHz 75.000000 MHz
DMT 0x12: 1024x768 75.028582 Hz 4:3 60.023 kHz 78.750000 MHz
DMT 0x24: 1280x1024 75.024675 Hz 5:4 79.976 kHz 135.000000 MHz
Standard Timings:
DMT 0x15: 1152x864 75.000000 Hz 4:3 67.500 kHz 108.000000 MHz
DMT 0x55: 1280x720 60.000000 Hz 16:9 45.000 kHz 74.250000 MHz
DMT 0x1c: 1280x800 59.810326 Hz 16:10 49.702 kHz 83.500000 MHz
DMT 0x23: 1280x1024 60.019740 Hz 5:4 63.981 kHz 108.000000 MHz
DMT 0x2f: 1440x900 59.887445 Hz 16:10 55.935 kHz 106.500000 MHz
DMT 0x53: 1600x900 60.000000 Hz 16:9 60.000 kHz 108.000000 MHz (RB)
DMT 0x3a: 1680x1050 59.954250 Hz 16:10 65.290 kHz 146.250000 MHz
DMT 0x52: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz
Detailed Timing Descriptors:
DTD 1: 3840x2160 59.996625 Hz 16:9 133.312 kHz 533.250000 MHz (697 mm x 392 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 54 Vpol N
Display Range Limits:
Monitor ranges (Bare Limits): 48-240 Hz V, 510-510 kHz H, max dotclock 2340 MHz
Display Product Name: 'Odyssey G80SD'
Display Product Serial Number: 'H1AK500000'
Extension blocks: 2
Checksum: 0xb3
----------------
Block 1, CTA-861 Extension Block:
Revision: 3
Underscans IT Video Formats by default
Basic audio support
Supports YCbCr 4:4:4
Supports YCbCr 4:2:2
Native detailed modes: 0
Video Data Block:
VIC 97: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz
VIC 95: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz
VIC 16: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz
VIC 63: 1920x1080 120.000000 Hz 16:9 135.000 kHz 297.000000 MHz
VIC 4: 1280x720 60.000000 Hz 16:9 45.000 kHz 74.250000 MHz
VIC 3: 720x480 59.940060 Hz 16:9 31.469 kHz 27.000000 MHz
VIC 118: 3840x2160 120.000000 Hz 16:9 270.000 kHz 1188.000000 MHz
Audio Data Block:
Linear PCM:
Max channels: 2
Supported sample rates (kHz): 48 44.1 32
Supported sample sizes (bits): 24 20 16
Speaker Allocation Data Block:
FL/FR - Front Left/Right
Colorimetry Data Block:
xvYCC601
xvYCC709
BT2020YCC
BT2020RGB
HDR Static Metadata Data Block:
Electro optical transfer functions:
Traditional gamma - SDR luminance range
SMPTE ST2084
Supported static metadata descriptors:
Static metadata type 1
Desired content max luminance: 96 (400.000 cd/m^2)
Desired content max frame-average luminance: 75 (253.810 cd/m^2)
Desired content min luminance: 3 (0.001 cd/m^2)
Vendor-Specific Video Data Block (HDR10+), OUI 90-84-8B:
Application Version: 57
Vendor-Specific Data Block (AMD), OUI 00-00-1A:
Version: 3.7
Minimum Refresh Rate: 48 Hz
Maximum Refresh Rate: 240 Hz
Flags 1.x: 0x00
Flags 2.x: 0xa0
Maximum luminance: 96 (400.000 cd/m^2)
Minimum luminance: 2 (0.000 cd/m^2)
Unknown: 0x4b 0x02
Detailed Timing Descriptors:
DTD 2: 2560x1440 59.950550 Hz 16:9 88.787 kHz 241.500000 MHz (697 mm x 392 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 33 Vpol N
DTD 3: 2560x1440 119.997589 Hz 16:9 182.996 kHz 497.750000 MHz (697 mm x 392 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 77 Vpol N
DTD 4: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz (697 mm x 392 mm)
Hfront 88 Hsync 44 Hback 148 Hpol P
Vfront 4 Vsync 5 Vback 36 Vpol P
Checksum: 0x48
----------------
Block 2, DisplayID Extension Block:
Version: 2.0
Extension Count: 0
Display Product Primary Use Case: Desktop gaming display
Unknown DisplayID Data Block (0x2a, length 18):
01 ff 0e 6f 08 ef 01 ff 09 9f 05 ef 01 7f 07 37 '...o...........7'
04 ef '..'
Checksum: 0x65
Checksum: 0x90
----------------
Preferred Video Timing if only Block 0 is parsed:
DTD 1: 3840x2160 59.996625 Hz 16:9 133.312 kHz 533.250000 MHz (697 mm x 392 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 54 Vpol N
----------------
Preferred Video Timings if Block 0 and CTA-861 Blocks are parsed:
VIC 97: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz
Hfront 176 Hsync 88 Hback 296 Hpol P
Vfront 8 Vsync 10 Vback 72 Vpol P
DTD 1: 3840x2160 59.996625 Hz 16:9 133.312 kHz 533.250000 MHz (697 mm x 392 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 54 Vpol N
----------------
Native Video Resolution:
3840x2160
----------------
edid-decode SHA: 84ddf9155376 2021-10-03 10:37:45
Warnings:
Block 1, CTA-861 Extension Block:
Video Data Block: VIC 97 is the preferred timing, overriding the first detailed timings. Is this intended?
EDID:
Base EDID: Some timings are out of range of the Monitor Ranges:
Vertical Freq: 30.000 - 120.000 Hz (Monitor: 48.000 - 240.000 Hz)
Horizontal Freq: 31.468 - 270.000 kHz (Monitor: 510.000 - 510.000 kHz)
Failures:
Block 1, CTA-861 Extension Block:
Missing VCDB, needed for Set Selectable RGB Quantization to avoid interop issues.
EDID:
DisplayID: Missing DisplayID Product Identification Data Block.
DisplayID: Missing DisplayID Display Parameters Data Block.
DisplayID: Missing DisplayID Display Interface Features Data Block.
DisplayID: Missing DisplayID Type VII Detailed Timing Data Block.
DisplayID: DisplayID expects at least one preferred timing.
EDID conformity: FAIL
So once again, I beseech you… what should be my next step here? Do I go try to talk to drm folks about this whole “display id 2.0” thing? Do I try to treat my monitor as defective with Samsung? Do I try a third graphics card from another vendor?