SAMSUNG 34-Inch doesn't work with desktop

[vickistan]

I bought a SAMSUNG 34-Inch 75Hz Refresh, WQHD Computer Monitor, 3440 x 1440p Resolution monitor. I can plug in my laptop (running Linux Mint 19.3) and it works with resolution 1920x1080. I tried to set my desktop to the higher resolution using the following commands:

1) cvt 3440 1440 75
The output was this:
3440x1440 74.95 Hz (CVT) hsync: 112.87 kHz; pclk: 532.75 MHz
Modeline "3440x1440_75.00" 532.75 3440 3704 4080 4720 1440 1443 1453 1506 -hsync +vsync

2) xrandr --newmode "3440x1440_75.00" 532.75 3440 3704 4080 4720 1440 1443 1453 1506 -hsync +vsync

3) xrandr --addmode HDMI-1 3440x1440_75.00

4) xrandr --outport HDMI-1 --mode 3440x1440_75.00

After running the commands, I connect the cable that came with the monitor from my Linux Desktop (running Linux Mint 20.2) to the HDMI-1 port on the new monitor. I see the POST and the Linux Mint menu, but once it proceeds, there is nothing on the screen. Is there something that has to be passed to Grub2 perhaps?

I reset the desktop to the old settings to see anything on the old monitor.

Here is the Graphics: section from inxi -Fx:

Graphics:
Device-1: AMD Bonaire XTX [Radeon R7 260X/360] vendor: XFX Pine
driver: radeon v: kernel bus ID: 02:00.0
Display: x11 server: X.Org 1.20.13 driver: ati,radeon
unloaded: fbdev,modesetting,vesa resolution: 1680x1050~60Hz
OpenGL: renderer: AMD BONAIRE (DRM 2.50.0 5.4.0-96-generic LLVM 12.0.0)
v: 4.5 Mesa 21.0.3 direct render: Yes

Appreciate any help!

Vickistan

[absque fenestris]

However, Samsung itself sees the 75 Hz setting as the possible maximum.
Samsung states 50 Hz or 60 Hz as the optimal setting (manual, page 46).



https://www.samsung.com/us/computing/mo ... xza/#specs
https://downloadcenter.samsung.com/cont ... 0A-Eng.pdf

[vickistan]

Ok, that makes sense. I tried the corresponding lines to the following:

cvt 3440 1440 60
cvt 2160 1440 60
cvt 1920 1200 50

None of them worked. How do I know what the values should be? I never thought I'd miss the Xconfigurator days, but I do today!

Thanks,
Vicki

[AndyMH]

Install read-edid from software manager, run get-edid twice.

First time to find out what bus the monitor is on:

Code: Select all

andy@T432 ~ $ sudo get-edid
[sudo] password for andy:          
This is read-edid version 3.0.2. Prepare for some fun.
Attempting to use i2c interface
No EDID on bus 1
No EDID on bus 2
No EDID on bus 5
No EDID on bus 6
No EDID on bus 7
No EDID on bus 8
No EDID on bus 9
3 potential busses found: 0 3 4  <<<<<<<< here
Will scan through until the first EDID is found.
Pass a bus number as an option to this program to go only for that one.
Bus 0 doesn't really have an EDID...
128-byte EDID successfully retrieved from i2c bus 3

bus 4 is what my external monitor is on, then

Code: Select all

andy@T432 ~ $ sudo get-edid -b 4 | parse-edid
4
This is read-edid version 3.0.2. Prepare for some fun.
Attempting to use i2c interface
Only trying 4 as per your request.
256-byte EDID successfully retrieved from i2c bus 4
Looks like i2c was successful. Have a good day.
Checksum Correct

Section "Monitor"
	Identifier "LG ULTRAWIDE"
	ModelName "LG ULTRAWIDE"
	VendorName "GSM"
	# Monitor Manufactured week 9 of 2017
	# EDID version 1.3
	# Digital Display
	DisplaySize 670 280
	Gamma 2.20
	Option "DPMS" "true"
	Horizsync 30-90
	VertRefresh 56-75
	# Maximum pixel clock is 240MHz
	#Not giving standard mode: 1152x864, 75Hz
	#Not giving standard mode: 1280x1024, 60Hz
	#Not giving standard mode: 1280x720, 60Hz
	#Not giving standard mode: 1600x900, 60Hz
	#Not giving standard mode: 1680x1050, 60Hz

	#Extension block found. Parsing...
	Modeline 	"Mode 11" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync 
	Modeline 	"Mode 0" 185.58 2560 2624 2688 2784 1080 1083 1093 1111 -hsync -vsync 
	Modeline 	"Mode 1" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync 
	Modeline 	"Mode 2" 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
	Modeline 	"Mode 3" 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync
	Modeline 	"Mode 4" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
	Modeline 	"Mode 5" 74.250 1920 2448 2492 2640 1080 1082 1089 1125 +hsync +vsync interlace
	Modeline 	"Mode 6" 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
	Modeline 	"Mode 7" 74.250 1920 2008 2052 2200 1080 1082 1087 1125 +hsync +vsync interlace
	Modeline 	"Mode 8" 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
	Modeline 	"Mode 9" 25.200 640 656 752 800 480 490 492 525 -hsync -vsync
	Modeline 	"Mode 10" 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
	Modeline 	"Mode 12" 74.25 1920 2008 2052 2200 540 542 547 562 +hsync +vsync interlace
	Modeline 	"Mode 13" 74.25 1280 1390 1430 1650 720 725 730 750 +hsync +vsync 
	Modeline 	"Mode 14" 27.00 720 736 798 858 480 489 495 525 -hsync -vsync 
	Option "PreferredMode" "Mode 11"
EndSection 

See if it gives a different modeline for your desired resolution. That was my problem with my LG ultrawide - CVT gave the wrong modeline. For me the "preferred" mode is Mode 0 (2560x1080), but linux thinks the preferred mode is Mode 11 (1920x1080).

[vickistan]

But since there is no output from the desktop to the monitor, I can't run that command while connected to the monitor unless I do it from ssh -X from a laptop. Is that going to give me the right results? Here is what I see when I run xrandr --current:

~$ xrandr --current
Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 16384 x 16384
eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 276mm x 1
55mm
1920x1080 60.00*+ 59.97 59.96 59.93 48.00
1680x1050 59.95 59.88
1600x1024 60.17
1400x1050 59.98
1600x900 59.99 59.94 59.95 59.82
1280x1024 60.02
1440x900 59.89
1400x900 59.96 59.88
1280x960 60.00
1440x810 60.00 59.97
1368x768 59.88 59.85
1360x768 59.80 59.96
1280x800 59.99 59.97 59.81 59.91
1152x864 60.00
1280x720 60.00 59.99 59.86 59.74
1024x768 60.04 60.00
960x720 60.00
928x696 60.05
896x672 60.01
1024x576 59.95 59.96 59.90 59.82
960x600 59.93 60.00
960x540 59.96 59.99 59.63 59.82
800x600 60.00 60.32 56.25
840x525 60.01 59.88

which is really odd since I only have a cable plugged into the only HDMI port on the computer and plugged into the monitor on port HDMI-2

Thanks,
Vickistan

[AndyMH]

But since there is no output from the desktop to the monitor, I can't run that command while connected to the monitor unless I do it from ssh -X from a laptop. Is that going to give me the right results? Here is what I see when I run xrandr --current:

connect it to the laptop where it works:

I can plug in my laptop (running Linux Mint 19.3) and it works with resolution 1920x1080.

What you are trying to do with is get the edid from the monitor to see if it gives you a different modeline to the one you get with cvt.

On your desktop are you connecting to the on-board graphics or do you have a separate video card?

[vickistan]

I am connecting to the only graphics port I see which appears to be a card. I don't quite know what to do with the output.

:~$ sudo get-edid -b 7 | parse-edid
7
This is read-edid version 3.0.2. Prepare for some fun.
Attempting to use i2c interface
Only trying 7 as per your request.
256-byte EDID successfully retrieved from i2c bus 7
Looks like i2c was successful. Have a good day.
Checksum Correct

Section "Monitor"
Identifier "S34J55x"
ModelName "S34J55x"
VendorName "SAM"
# Monitor Manufactured week 38 of 2021
# EDID version 1.3
# Digital Display
DisplaySize 800 330
Gamma 2.20
Option "DPMS" "true"
Horizsync 30-120
VertRefresh 50-75
# Maximum pixel clock is 410MHz
#Not giving standard mode: 1152x864, 75Hz
#Not giving standard mode: 1280x800, 60Hz
#Not giving standard mode: 1280x720, 60Hz
#Not giving standard mode: 1280x1024, 60Hz
#Not giving standard mode: 1440x900, 60Hz
#Not giving standard mode: 1600x900, 60Hz
#Not giving standard mode: 1680x1050, 60Hz

#Extension block found. Parsing...
#WARNING: I may have missed a mode (CEA mode 90)
Modeline "Mode 7" 265.25 3440 3488 3520 3600 1440 1443 1453 1474 +hsync -vsync
Modeline "Mode 0" 319.75 3440 3488 3520 3600 1440 1443 1453 1481 +hsync -vsync
Modeline "Mode 1" 148.500 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 2" 148.500 1920 2448 2492 2640 1080 1084 1089 1125 +hsync +vsync
Modeline "Mode 3" 74.250 1280 1390 1420 1650 720 725 730 750 +hsync +vsync
Modeline "Mode 4" 74.250 1280 1720 1760 1980 720 725 730 750 +hsync +vsync
Modeline "Mode 5" 27.027 720 736 798 858 480 489 495 525 -hsync -vsync
Modeline "Mode 6" 27.000 720 732 796 864 576 581 586 625 -hsync -vsync
Modeline "Mode 8" 198.00 2560 2808 2852 3000 1080 1084 1089 1100 +hsync +vsync
Modeline "Mode 9" 241.50 2560 2608 2640 2720 1440 1443 1448 1481 +hsync -vsync
Modeline "Mode 10" 148.50 1920 2008 2052 2200 1080 1084 1089 1125 +hsync +vsync
Option "PreferredMode" "Mode 7"
EndSection

[vickistan]

And also, how do I determine which output to use on my desktop? I know that the cable is plugged into HDMI-1 on the monitor, but how do I know what it should be on the desktop?

Also, is it possible to run the DIsplay app in the menu locally through a ssh -X connections?

Stupid questions are us,

Vickistan

[AndyMH]

From read-edid you have two 3440x1440 modelines in the monitor:

Code: Select all

Modeline "Mode 7" 265.25 3440 3488 3520 3600 1440 1443 1453 1474 +hsync -vsync
Modeline "Mode 0" 319.75 3440 3488 3520 3600 1440 1443 1453 1481 +hsync -vsync

And the preferred mode is mode 7. Neither are the same as the modeline you tried from cvt.

Code: Select all

Modeline "3440x1440_75.00" 532.75 3440 3704 4080 4720 1440 1443 1453 1506 -hsync +vsync

I tried to set my desktop to the higher resolution using the following commands:

How did you do that on the desktop if you say that you get no output on the monitor?

Is there something that has to be passed to Grub2 perhaps?

You can try adding nomodeset on boot, see answer 126 here:
https://askubuntu.com/questions/38780/h ... led-ubuntu
If that gives you a display then you can run xrandr to find out what port it is connecting on (it might not be HDMI-1) and then run the xrandr commands you tried originally

Code: Select all

2) xrandr --newmode "3440x1440_75.00" 532.75 3440 3704 4080 4720 1440 1443 1453 1506 -hsync +vsync
3) xrandr --addmode HDMI-1 3440x1440_75.00
4) xrandr --outport HDMI-1 --mode 3440x1440_75.00

but using the correct port and one of the modelines from the edid.

Note you have a typo, should be output not outport??

[vickistan]

Thanks, I made progress with the nomodeset. Now I can see the output on the new monitor, but the resolution resets to a cartoonish 1024x768. I can select the 3440x1440 in the display app, but whichever refresh rate I choose, it doesn't like it and reverts to 1024x768. It shows the error in the attachment.

Here is what xrandr --verbose

desktop:~/Pictures$ xrandr --verbose
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 1024 x 768, current 1024 x 768, maximum 3440 x 1440
default connected primary 1024x768+0+0 (0x527) normal (normal) 0mm x 0mm
Identifier: 0x526
Timestamp: 3133121
Subpixel: unknown
Clones:
CRTC: 0
CRTCs: 0
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
non-desktop: 0
supported: 0, 1
1024x768 (0x527) 59.769MHz *current
h: width 1024 start 0 end 0 total 1024 skew 0 clock 58.37KHz
v: height 768 start 0 end 0 total 768 clock 76.00Hz
"3440x1440_45.00" (0x542) 306.750MHz -HSync +VSync
h: width 3440 start 3664 end 4024 total 4608 skew 0 clock 66.57KHz
v: height 1440 start 1443 end 1453 total 1480 clock 44.98Hz
3440x1440_75.00 (0x580) 532.750MHz -HSync +VSync
h: width 3440 start 3704 end 4080 total 4720 skew 0 clock 112.87KHz
v: height 1440 start 1443 end 1453 total 1506 clock 74.95Hz
3440x1440_50.00 (0x585) 344.000MHz -HSync +VSync
h: width 3440 start 3672 end 4040 total 4640 skew 0 clock 74.14KHz
v: height 1440 start 1443 end 1453 total 1484 clock 49.96Hz
"3440x1440_49.96" (0x598) 343.750MHz -HSync +VSync
h: width 3440 start 3672 end 4040 total 4640 skew 0 clock 74.08KHz
v: height 1440 start 1443 end 1453 total 1484 clock 49.92Hz

[AndyMH]

I have run up to the limits of my expertise here, a quick google found this:
https://askubuntu.com/questions/971862/ ... ailable-si
suggesting that a

Code: Select all

dpkg-reconfigure lightdm && service lightdm restart

might fix it.

And mismatches between monitor.xml and the real one, but I'm out of my depth on that. I think unity-control-center is ubuntu only.

There are a number of modes at different refresh rates showing, e.g. 49.96Hz, you could try using cvt to generate modelines for those and try them, e.g. cvt 3440 1440 49.96 and see if any of them work.

Hopefully someone else with more knowledge will come along.