GDDCcontrol issues with NVIDIA drivers (i2c/monitor/display/DDC) - DP/HDMI failing

For me it just never works, neither a first time I’m running, nor a second.

I will try to run something that can expose/configure DDC in Windows real soon and report back.

Under Windows everything works beautifully!

Please fix your Linux drivers.

I tried to debug this issue by stepping through ddccontrol’s code, and it looks like its an issue with i2c indeed. Some commands succeed (like reading the (E)EDID) and others fail (especial reading the more advanced commands).

@Nvidia: please fix this!!

Aaron, please, do something about this bug. It’s a definite regression.

Bump!

I have a GeForce GTX 650 Ti BOOST DDC control works, but then the driver crashes. (With a Philips 226CL)

The same thing I have, didn’t found this thread earlier. Some stackdumps can be found there: https://devtalk.nvidia.com/default/topic/765571/linux/crash-when-using-dcc-i2c/.

If wanted I can move the posts to this thread.

Seems like no one at nvidia is interested in fixing i2c for their Linux drivers. This topic will soon be a year old ;-)

On the same PC everything works under Windows 7.

Well I can regulate the colour temperature on using curves on the software side. Most monitors don’t support more then 8 bit color control anyway, so anything less then 100% is going to quantize.
However changing the brightness, there is no replacement for that… (unless serious quantization is an option)

Well DDC works here. But it crashes the nvidia driver. You can see some stack dump from in the other thread I posted earlier.

EDIT: For clarification, DDC command DO succeed, but shortly after Nvidia starts freezing randomly for short periods, or freezes over completely. The short freezes seems to be triggered by some sort of interrupt since it’s kworker claiming the CPU time then.

EDIT: Ok the “solution” below didn’t work.
Failed before 1 hour of issuing 6 ddccontrol command every 5 minutes.


Invalid solution:

Found something that might fix my problem, not sure what side-effects it will have though (possible performance degradation):

No indication of issues here yet, but things might still fail later on.

cd /proc
cat interrupts  | grep nvidia | grep "\(.*\):"
#You want to take the highlighted numbers in the line, it's 44 for me here, might be different on your end.
cd irq/44
echo 1 > smp_affinity

Note: echo 1 means CPU afinity mask 0x000000001. Wich means only the first cpu will handle the events.
2 = 0x0…10 -> Only the second cpu.
3 = 0x0…11 -> First and second cpu and so fort.
Check the /proc/irq/??/smp_affinity_list for the human readable form

If I have the time I could construct a workaround. Looking at https://en.wikipedia.org/wiki/Digital_Visual_Interface pin 6 and 7 are DCC pins. Wich is basically I2C. For which you can get adaptors for: http://www.robot-electronics.co.uk/acatalog/USB_I2C.html I would just have to open up a spare DVI cable/piece to get the pins out. But still kinda ludicrous of course, since the video card already has them.

Hope some additional info might help

I have 3 of the same monitors (iiyama PL2778Q) connected to a GeForce GTX 760
two on DVI and one on DP.

Via ddccontrol I am able to control backlight on the monitor connected via DP but not on the two monitors connected via DVI.

The two DVI monitors has connection link: Dual and Signal: TMDS
The DP monitor has connection link: 4 lanes @ 2.79 Gbps and Signal: Displayport.

Below is some system information. Let me know there is any other information you need.

kernel: 3.14.14
nvidia module: 340.32

output from: ddccontrol -p -c -d -v

ddccontrol version 0.4.2
Copyright 2004-2005 Oleg I. Vdovikin (oleg@cs.msu.su)
Copyright 2004-2006 Nicolas Boichat (nicolas@boichat.ch)
This program comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of this program under the terms of the GNU General Public License.

ddcpci initing...
Starting /usr/bin/ddcpci 1 -1509765967 &...
Probing for available monitors...
Error while reading write message answer: Bad message
Reading EDID 0x50 failed.
Error while reading write message answer: Bad message
Reading EDID 0x50 failed.
Error while reading write message answer: Bad message
Reading EDID 0x50 failed.
I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/IVM6615.xml"
Document not parsed successfully.
Non-fatal error: Invalid response, magic is 0x6e
Invalid response, length is 110, should be 64 at most
Non-fatal error: Invalid response, magic is 0x6e
Invalid response, length is 110, should be 64 at most
Non-fatal error: Invalid response, magic is 0x6e
Invalid response, length is 110, should be 64 at most
I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/IVM6613.xml"
Document not parsed successfully.
Found PCI device (pci:01:00.0-0)
Found PCI device (pci:01:00.0-1)
Found PCI device (pci:01:00.0-2)
Device: pci:01:00.0-0
ddcci_open returned -2
Device: pci:01:00.0-1
ddcci_open returned -2
Device: pci:01:00.0-2
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-6)
Control redblack has been discarded by the caps string.
Control greenblack has been discarded by the caps string.
Control blueblack has been discarded by the caps string.
Control colortemp has been discarded by the caps string.
Control hpos has been discarded by the caps string.
Control vpos has been discarded by the caps string.
Control hsize has been discarded by the caps string.
Control vsize has been discarded by the caps string.
Control auto has been discarded by the caps string.
Control hpincushion has been discarded by the caps string.
Control hpincushionbalance has been discarded by the caps string.
Control vlinearity has been discarded by the caps string.
Control vlinearitybalance has been discarded by the caps string.
Control hmisconvergence has been discarded by the caps string.
Control vmisconvergence has been discarded by the caps string.
Control keybalance has been discarded by the caps string.
Control key has been discarded by the caps string.
Control tdistortionctrl has been discarded by the caps string.
Control tdistortionbalance has been discarded by the caps string.
Control bdistortionctrl has been discarded by the caps string.
Control bdistortionbalance has been discarded by the caps string.
Control tilt has been discarded by the caps string.
Control hmoire has been discarded by the caps string.
Control vmoire has been discarded by the caps string.
Control focus has been discarded by the caps string.
Control coarse has been discarded by the caps string.
Control fine has been discarded by the caps string.
Control settings has been discarded by the caps string.
Control audiospeakervolume has been discarded by the caps string.
Control degauss has been discarded by the caps string.
Control osdorientation has been discarded by the caps string.
Control dpms has been discarded by the caps string.
Control power has been discarded by the caps string.
ddcci_open returned 0
Found I2C device (dev:/dev/i2c-5)
Control brightness has been discarded by the caps string.
Control contrast has been discarded by the caps string.
Control red has been discarded by the caps string.
Control green has been discarded by the caps string.
Control blue has been discarded by the caps string.
Control redblack has been discarded by the caps string.
Control greenblack has been discarded by the caps string.
Control blueblack has been discarded by the caps string.
Control colortemp has been discarded by the caps string.
Control hpos has been discarded by the caps string.
Control vpos has been discarded by the caps string.
Control hsize has been discarded by the caps string.
Control vsize has been discarded by the caps string.
Control auto has been discarded by the caps string.
Control hpincushion has been discarded by the caps string.
Control hpincushionbalance has been discarded by the caps string.
Control vlinearity has been discarded by the caps string.
Control vlinearitybalance has been discarded by the caps string.
Control hmisconvergence has been discarded by the caps string.
Control vmisconvergence has been discarded by the caps string.
Control keybalance has been discarded by the caps string.
Control key has been discarded by the caps string.
Control tdistortionctrl has been discarded by the caps string.
Control tdistortionbalance has been discarded by the caps string.
Control bdistortionctrl has been discarded by the caps string.
Control bdistortionbalance has been discarded by the caps string.
Control tilt has been discarded by the caps string.
Control hmoire has been discarded by the caps string.
Control vmoire has been discarded by the caps string.
Control focus has been discarded by the caps string.
Control coarse has been discarded by the caps string.
Control fine has been discarded by the caps string.
Control defaults has been discarded by the caps string.
Coioctl(): Input/output error
ioctl returned -1
Reading EDID 0x50 failed.
ioctl(): Input/output error
ioctl returned -1
Reading EDID 0x50 failed.
ioctl(): Input/output error
ioctl returned -1
Reading EDID 0x50 failed.
ioctl(): Input/output error
ioctl returned -1
Reading EDID 0x50 failed.
Non-fatal error: Invalid response, magic is 0x6e
Invalid response, length is 110, should be 64 at most
Non-fatal error: Invalid response, magic is 0x6e
Invalid response, length is 110, should be 64 at most
Non-fatal error: Invalid response, magic is 0x6e
Invalid response, length is 110, should be 64 at most
I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/IVM6613.xml"
Document not parsed successfully.
I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/IVM6615.xml"
Document not parsed successfully.
ntrol defaultluma has been discarded by the caps string.
Control defaultgeom has been discarded by the caps string.
Control defaultcolor has been discarded by the caps string.
Control settings has been discarded by the caps string.
Control audiospeakervolume has been discarded by the caps string.
Control degauss has been discarded by the caps string.
Control secdegauss has been discarded by the caps string.
Control osdorientation has been discarded by the caps string.
Control inputsource has been discarded by the caps string.
Control dpms has been discarded by the caps string.
Control power has been discarded by the caps string.
ddcci_open returned 0
Found I2C device (dev:/dev/i2c-4)
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-3)
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-2)
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-1)
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-0)
Control brightness has been discarded by the caps string.
Control contrast has been discarded by the caps string.
Control red has been discarded by the caps string.
Control green has been discarded by the caps string.
Control blue has been discarded by the caps string.
Control redblack has been discarded by the caps string.
Control greenblack has been discarded by the caps string.
Control blueblack has been discarded by the caps string.
Control colortemp has been discarded by the caps string.
Control hpos has been discarded by the caps string.
Control vpos has been discarded by the caps string.
Control hsize has been discarded by the caps string.
Control vsize has been discarded by the caps string.
Control auto has been discarded by the caps string.
Control hpincushion has been discarded by the caps string.
Control hpincushionbalance has been discarded by the caps string.
Control vlinearity has been discarded by the caps string.
Control vlinearitybalance has been discarded by the caps string.
Control hmisconvergence has been discarded by the caps string.
Control vmisconvergence has been discarded by the caps string.
Control keybalance has been discarded by the caps string.
Control key has been discarded by the caps string.
Control tdistortionctrl has been discarded by the caps string.
Control tdistortionbalance has been discarded by the caps string.
Control bdistortionctrl has been discarded by the caps string.
Control bdistortionbalance has been discarded by the caps string.
Control tilt has been discarded by the caps string.
Control hmoire has been discarded by the caps string.
Control vmoire has been discarded by the caps string.
Control focus has been discarded by the caps string.
Control coarse has been discarded by the caps string.
Control fine has been discarded by the caps string.
Control defaults has been discarded by the caps string.
Control defaultluma has been discarded by the caps string.
Control defaultgeom has been discarded by the caps string.
Control defaultcolor has been discarded by the caps string.
Control settings has been discarded by the caps string.
Control audiospeakervolume has been discarded by the caps string.
Control degauss has been discarded by the caps string.
Control secdegauss has been discarded by the caps string.
Control osdorientation has been discarded by the caps string.
Control inputsource has been discarded by the caps string.
Control dpms has been discarded by the caps string.
Control power has been discarded by the caps string.
ddcci_open returned 0
Detected monitors :
 - Device: dev:/dev/i2c-6
   DDC/CI supported: Yes
   Monitor Name: VESA standard monitor
   Input type: Digital
  (Automatically selected)
 - Device: dev:/dev/i2c-5
   DDC/CI supported: Yes
   Monitor Name: VESA standard monitor
   Input type: Digital
 - Device: dev:/dev/i2c-0
   DDC/CI supported: Yes
   Monitor Name: VESA standard monitor
   Input type: Digital
Reading EDID and initializing DDC/CI at bus dev:/dev/i2c-6...
Serial number: 16843009
Manufactured: Week 255, 2013
EDID version: 1.4
Maximum size: 60 x 34 (cm)
Control redblack has been discarded by the caps string.
Control greenblack has been discardeInvalid response, length is 15, should be 8 at most
Invalid response, length is 15, should be 8 at most
Invalid response, length is 15, should be 8 at most
==>ddcpci is quitting.
d by the caps string.
Control blueblack has been discarded by the caps string.
Control colortemp has been discarded by the caps string.
Control hpos has been discarded by the caps string.
Control vpos has been discarded by the caps string.
Control hsize has been discarded by the caps string.
Control vsize has been discarded by the caps string.
Control auto has been discarded by the caps string.
Control hpincushion has been discarded by the caps string.
Control hpincushionbalance has been discarded by the caps string.
Control vlinearity has been discarded by the caps string.
Control vlinearitybalance has been discarded by the caps string.
Control hmisconvergence has been discarded by the caps string.
Control vmisconvergence has been discarded by the caps string.
Control keybalance has been discarded by the caps string.
Control key has been discarded by the caps string.
Control tdistortionctrl has been discarded by the caps string.
Control tdistortionbalance has been discarded by the caps string.
Control bdistortionctrl has been discarded by the caps string.
Control bdistortionbalance has been discarded by the caps string.
Control tilt has been discarded by the caps string.
Control hmoire has been discarded by the caps string.
Control vmoire has been discarded by the caps string.
Control focus has been discarded by the caps string.
Control coarse has been discarded by the caps string.
Control fine has been discarded by the caps string.
Control settings has been discarded by the caps string.
Control audiospeakervolume has been discarded by the caps string.
Control degauss has been discarded by the caps string.
Control osdorientation has been discarded by the caps string.
Control dpms has been discarded by the caps string.
Control power has been discarded by the caps string.

EDID readings:
	Plug and Play ID: IVM6615 [VESA standard monitor]
	Input type: Digital
=============================== WARNING ===============================
There is no support for your monitor in the database, but ddccontrol is
using a basic generic profile. Many controls will not be supported, and
some controls may not work as expected.
Please update ddccontrol-db, or, if you are already using the latest
version, please send the output of the following command to
ddccontrol-users@lists.sourceforge.net:

LANG= LC_ALL= ddccontrol -p -c -d

Thank you.
=============================== WARNING ===============================

Capabilities:
Raw output: (prot(monitor)type(LCD)model(XB2779QS)cmds(01 03 0C F3)vcp(02 04 05 06 08 0B 0C 10 12 14(02 05 08 0B) 16 18 1A 52 60(01 03 0F 11) B6 DF)mswhql(1)mccs_ver(2.1))
Parsed output: 
	VCP: 02 04 05 06 08 0b 0c 10 12 14 16 18 1a 52 60 b6 df 
	Type: Unknown

Controls (valid/current/max) [Description - Value name]:
Control 0x00: +/0/1   [???]
Control 0x02: +/2/255 C [Secondary Degauss]
Control 0x04: +/0/1 C [Restore Factory Defaults]
Control 0x05: +/0/1 C [Restore Brightness and Contrast]
Control 0x06: +/0/1 C [Restore Factory Default Geometry]
Control 0x08: +/0/1 C [Restore Factory Default Color]
Control 0x0b: +/2100/65535 C [???]
Control 0x0c: +/11/11 C [???]
Control 0x0e: +/0/100   [???]
Control 0x10: +/0/100 C [Brightness]
Control 0x12: +/50/100 C [Contrast]
Control 0x14: +/11/11 C [???]
Control 0x16: +/100/100 C [Red maximum level]
Control 0x18: +/100/100 C [Green maximum level]
Control 0x1a: +/100/100 C [Blue maximum level]
Control 0x1e: +/0/1   [???]
Control 0x20: +/0/100   [???]
Control 0x30: +/0/100   [???]
Control 0x3e: +/0/100   [???]
Control 0x52: +/96/255 C [???]
Control 0x60: +/15/17 C [Input Source Select]
Control 0x62: +/30/100   [???]
Control 0xac: +/8890/65535   [???]
Control 0xae: +/6000/65535   [???]
Control 0xb6: +/3/3 C [???]
Control 0xd6: +/1/5   [???]
Control 0xdf: +/513/65535 C [???]
Control 0xe5: +/0/0   [???]
Control 0xf1: +/1/4   [???]
Control 0xf2: +/0/255   [???]
Control 0xf3: +/642/0   [???]
Control 0xf5: +/0/65535   [???]
Control 0xfe: +/256/255   [???]
Control 0xff: +/18/255   [???]
ddcpci being released...

All this suggests to me that the problem lies somewhere in the DVI communication layer.
Are there any one of you that have observed similar conditions?

I found something that might fix the data corruption on the i2c bus, and some freezes/crashes.
Try to add that to xorg.conf or xorg.conf.d:

Section "Device"
    Identifier     "Device0"
    Driver         "nvidia"
    Option         "RegistryDwords" "RMUseSwI2c=0x01; RMI2cSpeed=100"
EndSection

These 2 “registry keys” come from the binary blob (“strings nvidia.ko | grep -i i2c”), they are part the same list as other documented keys which are used with the “RegistryDwords” option. RMI2cSpeed seems to be in KHz, but that’s just a guess because 100 works very well (DDC/CI standard speed is 100KHz) with the least data corruption (compared to 33, 200, 400 or no value set).
There is also a RMUseHwI2c which adds an i2c-device but makes ddccontrol crash.

I also had to recompile ddccontrol after increasing the value of the DELAY macro from 45000 to 50000 in the file src/lib/ddcci.c because there was some leading zero bytes before the actual DDC response.

OMG, thank you very much! Gddccontrol now works here!!

I’m adding this information to the OP now!

You’re a genius!

sandipt, aplattner, other NVIDIA Linux developers::

Please, change the defaults in the driver!

Hi
thank you for your advice but it does not work for me . LG Plasma (32PC5RV-TD ) recongnized as VESA Standard frame buffer and ddcontrol shows me chinese alphabet in the output . No matter what does it means .
I use Geforce 200 1 Gb DDr with DVI output to HDMI input of LG Plasma (Ubuntu13.10 , nvidia driver 337.25 (32Bits) .

hier the output :
sudo ddccontrol -p
Password:
ddccontrol version 0.4.2
Copyright 2004-2005 Oleg I. Vdovikin (oleg@cs.msu.su)
Copyright 2004-2006 Nicolas Boichat (nicolas@boichat.ch)
This program comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of this program under the terms of the GNU General Public License.

正在探测可用的显示器…I/O warning : failed to load external entity “/usr/share/ddccontrol-db/monitor/GSM75D9.xml”
文档语法分析不成功.

检查到的显示器:

  • 设备: dev:/dev/i2c-2
    DDC/CI 支持: 否
    显示器名称: VESA standard monitor
    输入类型: 数字
    没有支持 DDC/CI 的显示器存在.
    如果你的图形卡需要它,请检查所有的必需的内核模块已经加载 (i2c-dev, 以及你的 framebuffer 驱动).

For the chinese part, you can try launching the command like that:

LANG= LC_ALL= sudo ddccontrol -p

thnx for the advice alexisdm. this the what the commeand gives:

ddccontrol version 0.4.2
Copyright 2004-2005 Oleg I. Vdovikin (oleg@cs.msu.su)
Copyright 2004-2006 Nicolas Boichat (nicolas@boichat.ch)
This program comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of this program under the terms of the GNU General Public License.

Probing for available monitors.......I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/GSM75D9.xml"
Document not parsed successfully.
.
Detected monitors :
 - Device: dev:/dev/i2c-2
   DDC/CI supported: No
   Monitor Name: VESA standard monitor
   Input type: Digital
No monitor supporting DDC/CI available.
If your graphics card need it, please check all the required kernel modules are loaded (i2c-dev, and your framebuffer driver).

Have you actually restarted the X server? (reboot will suffice as well)

Please post the output of this command:

sudo ddccontrol -p -c -d -v -v

yes i did . the LG ist still not recognized .

LANG=LC_ALL= sudo ddccontrol -p -c -d -v -v
ddccontrol version 0.4.2
Copyright 2004-2005 Oleg I. Vdovikin (oleg@cs.msu.su)
Copyright 2004-2006 Nicolas Boichat (nicolas@boichat.ch)
This program comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of this program under the terms of the GNU General Public License.

ddcpci initing...
Starting /usr/bin/ddcpci 2 1107403375 &...
Probing for available monitors...
==>Received!
==>Listing...
==>01:00.0 vendor=10de device=0a65 class=0300 irq=50 base0=f2000000 size0=1000000
==>Supported
==>01:00.0-0
==>01:00.0-1
==>01:00.0-2
==>EOL
Found PCI device (pci:01:00.0-0)
Found PCI device (pci:01:00.0-1)
Found PCI device (pci:01:00.0-2)
Device: pci:01:00.0-0
==>Received!
==>Opening...
==>01:00.0-0
==>01:00.0 vendor=10de device=0a65 class=0300 irq=50 base0=f2000000 size0=1000000
==>Opened (status=0)...
==>Received!
==>Data, mquery->flags = 0
Error while reading write message answer: Bad message
Reading EDID 0x50 failed.
ddcci_open returned -2
Device: pci:01:00.0-1
==>Received!
==>Opening...
==>01:00.0-1
==>01:00.0 vendor=10de device=0a65 class=0300 irq=50 base0=f2000000 size0=1000000
==>Opened (status=0)...
==>Received!
==>Data, mquery->flags = 0
Error while reading write message answer: Bad message
Reading EDID 0x50 failed.
ddcci_open returned -2
Device: pci:01:00.0-2
==>Received!
==>Opening...
==>01:00.0-2
==>01:00.0 vendor=10de device=0a65 class=0300 irq=50 base0=f2000000 size0=1000000
==>Opened (status=0)...
==>Received!
==>Data, mquery->flags = 0
Error while reading write message answer: Bad message
Reading EDID 0x50 failed.
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-4)
ioctl(): Input/output error
ioctl returned -1
Reading EDID 0x50 failed.
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-3)
ioctl(): Input/output error
ioctl returned -1
Reading EDID 0x50 failed.
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-2)
Send: 00                                              | .               
Recv: 00                                              | .               
ioctl(): Input/output error
ioctl returned -1
ioctl(): Input/output error
ioctl returned -1
ioctl(): Input/output error
ioctl returned -1
I/O warning : failed to load external entity "/usr/share/ddccontrol-db/monitor/GSM75D9.xml"
Document not parsed successfully.
Control brightness has been discarded by the caps string.
Control contrast has been discarded by the caps string.
Control red has been discarded by the caps string.
Control green has been discarded by the caps string.
Control blue has been discarded by the caps string.
Control redblack has been discarded by the caps string.
Control greenblack has been discarded by the caps string.
Control blueblack has been discarded by the caps string.
Control colortemp has been discarded by the caps string.
Control hpos has been discarded by the caps string.
Control vpos has been discarded by the caps string.
Control hsize has been discarded by the caps string.
Control vsize has been discarded by the caps string.
Control auto has been discarded by the caps string.
Control hpincushion has been discarded by the caps string.
Control hpincushionbalance has been discarded by the caps string.
Control vlinearity has been discarded by the caps string.
Control vlinearitybalance has been discarded by the caps string.
Control hmisconvergence has been discarded by the caps string.
Control vmisconvergence has been discarded by the caps string.
Control keybalance has been discarded by the caps string.
Control key has been discarded by the caps string.
Control tdistortionctrl has been discarded by the caps string.
Control tdistortionbalance has been discarded by the caps string.
Control bdistortionctrl has been discarded by the caps string.
Control bdistortionbalance has been discarded by the caps string.
Control tilt has been discarded by the caps string.
Control hmoire has been discarded by the caps string.
Control vmoire has been discarded by the caps string.
Control focus has been discarded by the caps string.
Control coarse has been discarded by the caps string.
Control fine has been discarded by the caps string.
Control defaults has been discarded by the caps string.
Control defaultluma has been discarded by the caps string.
Control defaultgeom has been discarded by the caps string.
Control defaultcolor has been discarded by the caps string.
Control settings has been discarded by the caps string.
Control audiospeakervolume has been discarded by the caps string.
Control degauss has been discarded by the caps string.
Control osdorientation has been discarded by the caps string.
Control inputsource has been discarded by the caps string.
Control dpms has been discarded by the caps string.
Control power has been discarded by the caps string.
ioctl(): Input/output error
ioctl returned -1
ddcci_open returned -1
Found I2C device (dev:/dev/i2c-1)
Send: 00                                              | .               
Recv: 00                                              | .               
Corrupted EDID at 0x50.
ddcci_open returned -2
Found I2C device (dev:/dev/i2c-0)
Send: 00                                              | .               
Recv: 00                                              | .               
Corrupted EDID at 0x50.
ddcci_open returned -2
Detected monitors :
 - Device: dev:/dev/i2c-2
   DDC/CI supported: No
   Monitor Name: VESA standard monitor
   Input type: Digital
No monitor supporting DDC/CI available.
If your graphics card need it, please check all the required kernel modules are loaded (i2c-dev, and your framebuffer driver).
ddcpci being released...
==>Received!
==>Quitting...
==>ddcpci is quitting.