Hello, friends!
I have been struggling for a long time with the incorrect determination (setting) of the monitor positions (which one is on the left, which one is on the right), plus a problem with a random black screen appeared (often appeared on tiled WMs). My knowledge is clearly not enough to solve the problem on my own, and asking about such trifles is inconvenient. And how can I ask a question if I myself do not understand what to ask?
I always thought that the first port (DP-1) is the monitor on the left, the second port (DP-2, DP-3, etc.) is the monitor on the right. Logical, right? But it is not!
The installers of different OS randomly(?) selected the main monitor.
After installation, different OS behaved differently, someone thought that DP-1 was the monitor on the left, someone thought that DP-3 was the monitor on the left. I had to forcibly set which monitor was on the left in the Gnome settings. Do you think thatâs all? Absolutely not!
When exiting screen lock, sleep or suspend mode, the login screen randomly chose which monitor to assign to the left (main) monitor. Of course, this is not a fatal problem, but it really annoyed me!
In addition to the above, application windows were placed in random places, I usually use the browser on the second (right) monitor, but after exiting sleep mode it could appear on the first monitor in a random place - I was outraged!
Any attempts to connect monitors to other ports (I tried only DP*) of the video card did not work.
And then I thought, by what logic does the OS select which monitor is on the left? By name? By port number? By monitor serial number?
I read the EDID of the IMA monitor:
alevykh@prsnl:~$ edid-decode imagic-edid.old.bin
edid-decode (hex):
00 ff ff ff ff ff ff 00 25 a1 00 27 00 00 00 00
00 0a 01 04 b5 3c 22 78 33 af f0 ab 50 53 a3 22
11 50 54 bd 6b 80 81 c0 81 80 95 00 a9 c0 b3 00
d1 c0 01 01 01 01 4d d0 00 a0 f0 70 3e 80 30 20
35 00 59 53 21 00 00 1a 00 00 00 ff 30 30 30 30
30 30 30 30 30 30 30 30 30 30 00 00 00 fd 00 30
3e de de 3c 01 0a 20 20 20 20 20 20 00 00 00 fc
00 4d 32 37 38 55 0a 20 20 20 20 20 20 20 01 77
02 03 18 74 4b 90 9f 85 94 04 13 03 12 01 02 11
23 09 07 07 83 01 00 00 04 74 00 30 f2 70 5a 80
b0 58 36 00 59 53 21 00 00 1a 56 5e 00 a0 a0 a0
29 50 30 20 35 00 59 53 21 00 00 1e 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 58
----------------
Block 0, Base EDID:
EDID Structure Version & Revision: 1.4
Vendor & Product Identification:
Manufacturer: IMA
Model: 9984
Made in: 2000
Basic Display Parameters & Features:
Digital display
Bits per primary color channel: 10
DisplayPort interface
Maximum image size: 60 cm x 34 cm
Gamma: 2.20
DPMS levels: Off
Supported color formats: RGB 4:4:4, YCrCb 4:2:2
First detailed timing includes the native pixel format and preferred refresh rate
Display supports continuous frequencies
Color Characteristics:
Red : 0.6699, 0.3144
Green: 0.3271, 0.6396
Blue : 0.1357, 0.0693
White: 0.3125, 0.3281
Established Timings I & II:
IBM : 720x400 70.081663 Hz 9:5 31.467 kHz 28.320000 MHz
DMT 0x04: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz
Apple : 640x480 66.666667 Hz 4:3 35.000 kHz 30.240000 MHz
DMT 0x05: 640x480 72.808802 Hz 4:3 37.861 kHz 31.500000 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 0x0b: 800x600 75.000000 Hz 4:3 46.875 kHz 49.500000 MHz
Apple : 832x624 74.551266 Hz 4:3 49.726 kHz 57.284000 MHz
DMT 0x10: 1024x768 60.003840 Hz 4:3 48.363 kHz 65.000000 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
Apple : 1152x870 75.061550 Hz 192:145 68.681 kHz 100.000000 MHz
Standard Timings:
DMT 0x55: 1280x720 60.000000 Hz 16:9 45.000 kHz 74.250000 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 (601 mm x 339 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 54 Vpol N
Display Product Serial Number: '0000000000000'
Display Range Limits:
Monitor ranges (Range Limits Only): 48-62 Hz V, 222-222 kHz H, max dotclock 600 MHz
Display Product Name: 'M278U'
Extension blocks: 1
Checksum: 0x77
----------------
Block 1, CTA-861 Extension Block:
Revision: 3
Basic audio support
Supports YCbCr 4:4:4
Supports YCbCr 4:2:2
Native detailed modes: 4
Video Data Block:
VIC 16: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz (native)
VIC 31: 1920x1080 50.000000 Hz 16:9 56.250 kHz 148.500000 MHz (native)
VIC 5: 1920x1080i 60.000000 Hz 16:9 33.750 kHz 74.250000 MHz (native)
VIC 20: 1920x1080i 50.000000 Hz 16:9 28.125 kHz 74.250000 MHz (native)
VIC 4: 1280x720 60.000000 Hz 16:9 45.000 kHz 74.250000 MHz
VIC 19: 1280x720 50.000000 Hz 16:9 37.500 kHz 74.250000 MHz
VIC 3: 720x480 59.940060 Hz 16:9 31.469 kHz 27.000000 MHz
VIC 18: 720x576 50.000000 Hz 16:9 31.250 kHz 27.000000 MHz
VIC 1: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz
VIC 2: 720x480 59.940060 Hz 4:3 31.469 kHz 27.000000 MHz
VIC 17: 720x576 50.000000 Hz 4:3 31.250 kHz 27.000000 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
Detailed Timing Descriptors:
DTD 2: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz (601 mm x 339 mm)
Hfront 176 Hsync 88 Hback 296 Hpol P
Vfront 3 Vsync 6 Vback 81 Vpol N
DTD 3: 2560x1440 59.950550 Hz 16:9 88.787 kHz 241.500000 MHz (601 mm x 339 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 33 Vpol P
Checksum: 0x58 Unused space in Extension Block: 67 bytes
As you can see, the EDID does not look quite right, as if it was specially modified. The serial number is missing. I corrected it, added the serial number, because I did not understand how the video card selects the order of monitors. Maybe it really is by serial number? But I did not flash it, because I read this You can kill your PC
And then I decided, why not try HDMI? Connected M278U to HDMI. Then
$systemctl reboot
As a result:
NVIDIA port | MONITOR port
------------------|---------------------|
|HDMI-1 | works fine
HDMI |---------------------|
|HDMI-2 | doesn't work (still the same problem)
|---------------------|
|HDMI-3 | doesn't work (still the same problem)
----------------------------------------|
and EDID now is
alevykh@prsnl:~$ sudo edid-decode /sys/class/drm/card1-HDMI-A-1/edid
edid-decode (hex):
00 ff ff ff ff ff ff 00 25 a1 00 27 01 00 00 00
0c 21 01 03 80 3c 22 78 2a 59 95 af 4f 42 af 26
0f 50 54 21 08 00 81 00 81 40 81 80 81 c0 a9 c0
95 00 b3 00 a9 40 08 e8 00 30 f2 70 5a 80 b0 58
4a 00 59 53 21 00 00 1e 00 00 00 fd 00 30 3c 17
e1 3c 00 0a 20 20 20 20 20 20 02 3a 80 18 71 38
2d 40 58 2c 45 00 60 63 21 00 00 1e 00 00 00 fc
00 4d 32 37 38 55 0a 20 20 20 20 20 20 20 01 8b
02 03 36 f1 4a 61 01 02 10 05 04 03 13 1f 01 23
09 07 07 83 01 00 00 6d 03 0c 00 10 00 38 3c 20
00 60 01 01 01 67 d8 5d c4 01 78 80 00 68 1a 00
00 01 01 30 3c ed 6a 5e 00 a0 a0 a0 29 50 30 20
35 00 59 53 21 00 00 1a 04 74 00 30 f2 70 5a 80
b0 58 36 00 59 53 21 00 00 1e 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 c6
----------------
Block 0, Base EDID:
EDID Structure Version & Revision: 1.3
Vendor & Product Identification:
Manufacturer: IMA
Model: 9984
Serial Number: 1 (0x00000001)
Made in: week 12 of 2023
Basic Display Parameters & Features:
Digital display
Maximum image size: 60 cm x 34 cm
Gamma: 2.20
DPMS levels: Off
RGB color display
First detailed timing is the preferred timing
Color Characteristics:
Red : 0.6845, 0.3095
Green: 0.2597, 0.6845
Blue : 0.1503, 0.0595
White: 0.3134, 0.3291
Established Timings I & II:
DMT 0x04: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz
DMT 0x09: 800x600 60.316541 Hz 4:3 37.879 kHz 40.000000 MHz
DMT 0x10: 1024x768 60.003840 Hz 4:3 48.363 kHz 65.000000 MHz
Standard Timings:
DMT 0x1c: 1280x800 59.810326 Hz 16:10 49.702 kHz 83.500000 MHz
DMT 0x20: 1280x960 60.000000 Hz 4:3 60.000 kHz 108.000000 MHz
DMT 0x23: 1280x1024 60.019740 Hz 5:4 63.981 kHz 108.000000 MHz
DMT 0x55: 1280x720 60.000000 Hz 16:9 45.000 kHz 74.250000 MHz
DMT 0x53: 1600x900 60.000000 Hz 16:9 60.000 kHz 108.000000 MHz (RB)
DMT 0x2f: 1440x900 59.887445 Hz 16:10 55.935 kHz 106.500000 MHz
DMT 0x3a: 1680x1050 59.954250 Hz 16:10 65.290 kHz 146.250000 MHz
DMT 0x33: 1600x1200 60.000000 Hz 4:3 75.000 kHz 162.000000 MHz
Detailed Timing Descriptors:
DTD 1: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz (601 mm x 339 mm)
Hfront 176 Hsync 88 Hback 296 Hpol P
Vfront 4 Vsync 10 Vback 76 Vpol P
Display Range Limits:
Monitor ranges (GTF): 48-60 Hz V, 23-225 kHz H, max dotclock 600 MHz
DTD 2: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz (608 mm x 355 mm)
Hfront 88 Hsync 44 Hback 148 Hpol P
Vfront 4 Vsync 5 Vback 36 Vpol P
Display Product Name: 'M278U'
Extension blocks: 1
Checksum: 0x8b
----------------
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: 1
Video Data Block:
VIC 97: 3840x2160 60.000000 Hz 16:9 135.000 kHz 594.000000 MHz
VIC 1: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 MHz
VIC 2: 720x480 59.940060 Hz 4:3 31.469 kHz 27.000000 MHz
VIC 16: 1920x1080 60.000000 Hz 16:9 67.500 kHz 148.500000 MHz
VIC 5: 1920x1080i 60.000000 Hz 16:9 33.750 kHz 74.250000 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 19: 1280x720 50.000000 Hz 16:9 37.500 kHz 74.250000 MHz
VIC 31: 1920x1080 50.000000 Hz 16:9 56.250 kHz 148.500000 MHz
VIC 1: 640x480 59.940476 Hz 4:3 31.469 kHz 25.175000 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
Vendor-Specific Data Block (HDMI), OUI 00-0C-03:
Source physical address: 1.0.0.0
DC_36bit
DC_30bit
DC_Y444
Maximum TMDS clock: 300 MHz
Extended HDMI video details:
HDMI VICs:
HDMI VIC 1: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz
HDMI VIC 1: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz
HDMI VIC 1: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz
Vendor-Specific Data Block (HDMI Forum), OUI C4-5D-D8:
Version: 1
Maximum TMDS Character Rate: 600 MHz
SCDC Present
Vendor-Specific Data Block (AMD), OUI 00-00-1A:
Version: 1.1
Minimum Refresh Rate: 48 Hz
Maximum Refresh Rate: 60 Hz
Flags 1.x: 0xed (MCCS)
Detailed Timing Descriptors:
DTD 3: 2560x1440 60.000199 Hz 16:9 88.860 kHz 241.700000 MHz (601 mm x 339 mm)
Hfront 48 Hsync 32 Hback 80 Hpol P
Vfront 3 Vsync 5 Vback 33 Vpol N
DTD 4: 3840x2160 30.000000 Hz 16:9 67.500 kHz 297.000000 MHz (601 mm x 339 mm)
Hfront 176 Hsync 88 Hback 296 Hpol P
Vfront 3 Vsync 6 Vback 81 Vpol P
Checksum: 0xc6 Unused space in Extension Block: 37 bytes
Note that the EDID on HDMI port is now different! Added serial number; another version of the EDID structure, as well as some other parameters.
And now everything works as it should! After exiting all modes (sleep, lock, suspend), the monitors are detected correctly, applications remain in their places (x,y) and retain their sizes. And also on the login screen (on both monitors) the desktop wallpaper is now displayed correctly (BONUS for me )!
So I have a few questions for you, experienced people:
- Why is the EDID of one monitor different on different ports (itâs fake monitor)??
- By what logic and who chooses which monitor is on the left at the initial stage of OS booting?