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I have a monitor LG E2251 (monitor details).

My computer was connected to the monitor via DVI-I cable; after the power supply broke, the display went black. I rebooted the system and all seemed ok. I pass the POST as usual, however I cannot see the GUI nor CLI when connected with DVI-I. I believe the EDID code for DVI-I has been corrupted. I also tried with other 2 connections: whether HDMI doesn't present any damge,I get the following message for DVI-I

nouveau 0000:01:00.0: DRM: VRAM: 1024 MiB [ 9.292129] nouveau 0000:01:00.0: DRM: GART: 1048576 MiB [ 9.292133] nouveau 0000:01:00.0: DRM: TMDS table version 2.0 [ 9.292135] nouveau 0000:01:00.0: DRM: DCB version 4.0 [ 9.292137] nouveau 0000:01:00.0: DRM: DCB outp 00: 01000302 00020030 [ 9.292139] nouveau 0000:01:00.0: DRM: DCB outp 01: 02000300 00000000 [ 9.292141] nouveau 0000:01:00.0: DRM: DCB outp 02: 02011362 00020010 [ 9.292143] nouveau 0000:01:00.0: DRM: DCB outp 03: 01022310 00000000 [ 9.292145] nouveau 0000:01:00.0: DRM: DCB conn 00: 00001030 [ 9.292146] nouveau 0000:01:00.0: DRM: DCB conn 01: 00002161 [ 9.292148] nouveau 0000:01:00.0: DRM: DCB conn 02: 00000200 [ 9.296293] [drm] Supports vblank timestamp caching Rev 2 (21.10.2013). [ 9.296294] [drm] Driver supports precise vblank timestamp query. [ 9.309393] nouveau 0000:01:00.0: DRM: MM: using COPY for buffer copies [drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is invalid, remainder is 185 [ 9.449801] nouveau 0000:01:00.0: DVI-I-1: EDID block 0 invalid. [ 9.449803] nouveau 0000:01:00.0: DRM: DDC responded, but no EDID for DVI-I-1 [ 9.470675] nouveau 0000:01:00.0: No connectors reported connected with modes [ 9.470678] [drm] Cannot find any crtc or sizes - going 1024x768 [ 9.472105] nouveau 0000:01:00.0: DRM: allocated 1024x768 fb: 0x70000, bo ffff9d41b8eafc00 [ 9.472196] fbcon: nouveaufb (fb0) is primary device [ 9.474979] Console: switching to colour frame buffer device 128x48 [ 9.476170] nouveau 0000:01:00.0: fb0: nouveaufb frame buffer device [ 9.508021] [drm] Initialized nouveau 1.3.1 20120801 for 0000:01:00.0 on minor 0

and a similar one for VGA

 [drm:drm_edid_block_valid [drm]] *ERROR* EDID checksum is invalid, remainder is 198 [ 95.783329] nouveau 0000:01:00.0: VGA-1: EDID block 0 invalid. [ 95.783331] nouveau 0000:01:00.0: DRM: DDC responded, but no EDID for VGA-1

MY APPROACH

  • installed i2c-tools on my debian machine.
  • found i2c-1 to be my DVI interface
  • with i2cdump -y 1 0x50 I can dump the EDID code.

i2cset

However, when I want to set a block of bytes with
i2cset -y 1 0x50 0x00 0x00 0xff i EDID does not change.

How can I correct those EDID? Is there a fast solution in the UserSpace, without assembly programming?

I say I'm new to EDID, nouveau driver, I2C or SMBus communication. Any advice and correction is appreciated.

It looks like I could send BLOCKs of bytes on that I2C BUS i2cdetect -F 1:

Functionalities implemented by /dev/i2c-1: I2C Block Write yes I2C Block Read yes ...

but I don't know what's wrong.

LINKS

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  • Can you try to connect another monitor by DVI or VGA? Will it work? I read Wikipedia article and found: "The EDID is often stored in the monitor in a memory device called a serial PROM (programmable read-only memory) or EEPROM (electrically erasable PROM)". There is no separate EDID for HDMI, but HDMI connection works in your case. May be something happens with VGA/DVI controller? Commented May 22, 2019 at 13:49

2 Answers 2

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I don't know if this helps, but I found the EDID dumps matching your monitor model (to compare with your dump).

LG Electronics Inc. (GoldStar Technology, Inc.) E2251

https://github.com/linuxhw/EDID

MFG Model Name Res Size Inch Made ID Goldstar GSM586D E2251 1920x1080 480x270mm 21.7 2011 8A799 Goldstar GSM586E E2251 1920x1080 480x270mm 21.7 2011 011A9 Goldstar GSM586E E2251 1920x1080 480x270mm 21.7 2011 2F15B Goldstar GSM586E E2251 1920x1080 480x270mm 21.7 2011 F721B Goldstar GSM586F E2251 1920x1080 480x270mm 21.7 2011 2CA66

If you have Windows you should try Powerstrip to read/write the EDID data.

A great article covering this topic: Change the display EDID (google translated from German)

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The main problem with adjusting monitor EDID is that it's EEPROM is often switched to Write-protected mode and can't be written directly.

Unfortunately, most of the scripts designed for writing EDID just silently ignores the situation - writing is silently finished, but actually nothing changed. That's quite confusing, so I forked nowadays-unsupported edid-rw tool and create variant with improved verification/documentation: - edid-checked-writer

It provides the fail/sucess message like:

  • OK: New EDID written and verified
  • ERROR: Failed writing new EDID, maybe device is write-protected

So those messages actually tells if EDID in monitor is read-only or writable.

And if it is read-only - the only way is injecting display emulator with pass-through output. Such emulators typically have a writable EDID that is reported to the signal source and the video pass-through signal would get to the monitor.

Typically, such emulator should be plugged between the signal source and monitor cable and obviously should have HDMI/DVI/VGA correspond to signal source

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