Xfce Forum

Mo_B

Member

From: Germany

Registered: 2016-03-04

Posts: 68

Loosing panels on EDID change via KVM switch

Hi,

I try to use a PKS0802A10 KVM switch on DisplayPorts. The EDID emulation is buggy and I always loose my window setup and panels are disappearing.
I'm logging the EDID via

ddcutil detect

With EDID emulation enabled and connected to the machine, I have this:

# ddcutil detect
Display 1
   I2C bus:  /dev/i2c-5
   DRM connector:           card0-DP-1
   EDID synopsis:
      Mfg id:               DEL - Dell Inc.
      Model:                DELL U2518D
      Product code:         16698  (0x413a)
      Serial number:        3C4YP838983L
      Binary serial number: 959984460 (0x3938334c)
      Manufacture year:     2018,  Week: 10
   VCP version:         2.1

Display 2
   I2C bus:  /dev/i2c-6
   DRM connector:           card0-DP-2
   EDID synopsis:
      Mfg id:               DEL - Dell Inc.
      Model:                DELL U2518D
      Product code:         16698  (0x413a)
      Serial number:        3C4YP98F914L
      Binary serial number: 959525964 (0x3931344c)
      Manufacture year:     2019,  Week: 33
   VCP version:         2.1

When disconnected and switched to a different channel I have this:

# ddcutil detect
Invalid display
   I2C bus:  /dev/i2c-5
   DRM connector:           card0-DP-1
   EDID synopsis:
      Mfg id:               DEL - Dell Inc.
      Model:                DELL U2518D
      Product code:         16698  (0x413a)
      Serial number:        3C4YP838983L
      Binary serial number: 959984460 (0x3938334c)
      Manufacture year:     2018,  Week: 10
   This monitor does not support DDC/CI. (I2C slave address x37 is unresponsive.)

Invalid display
   I2C bus:  /dev/i2c-6
   DRM connector:           card0-DP-2
   EDID synopsis:
      Mfg id:               DEL - Dell Inc.
      Model:                DELL U2518D
      Product code:         16698  (0x413a)
      Serial number:        3C4YP98F914L
      Binary serial number: 959525964 (0x3931344c)
      Manufacture year:     2019,  Week: 33
   This monitor does not support DDC/CI. (I2C slave address x37 is unresponsive.)

Something buggy with that KVM switch and no way to update firmware...
So I disable the EDID emulation, which leads to "No displays found" when disconnected.

The result for the Xfce session is always the same: I loose my window positions AND the panels have disappeared.
Loosing the positions might be as expected if not storing and restoring the previous positions somehow. But why do the panels disappear? They can be always restored by a simple xfce4-panel --restart. But why do I need that?

Next I try to workaround that by custom EDIDs. At least the desktop computer always has the same monitor setup. So I copied from /sys/class/drm/card0-*/edid and created that

/etc/X11/xorg.conf.d/20-intel.conf:

Section "Device"
    Identifier "Intel Graphics"
    Option "CustomEDID" "DP-1:/etc/X11/edid-dp1.bin;DP-2:/etc/X11/edid-dp2.bin"
EndSection

Section "Monitor"
    Identifier  "Monitor1"
    Option      "PreferredMode" "2560x1440"
    Option      "Position" "0 0"
EndSection

Section "Monitor"
    Identifier  "Monitor2"
    Option      "PreferredMode" "2560x1440"
    Option      "RightOf" "Monitor1"
EndSection

Section "Screen"
    Identifier  "Screen0"
    Device      "Intel Graphics"
    Monitor     "Monitor1"
    DefaultDepth    24
    SubSection "Display"
        Depth 24
        Modes "2560x1440"
    EndSubSection
EndSection

Section "ServerLayout"
    Identifier  "Layout0"
    Screen  0   "Screen0"
EndSection

But CustomEDID is ignored by Xorg:

# grep EDID /var/log/Xorg.0.log
[397828.615] (II) modeset(0): EDID for output DP-1
[397828.615] (II) modeset(0): EDID Version: 1.4
[397828.616] (II) modeset(0): Number of EDID sections to follow: 1
[397828.616] (II) modeset(0): EDID (in hex):
[397828.626] (II) modeset(0): EDID for output HDMI-1
[397828.650] (II) modeset(0): EDID for output DP-2
[397828.650] (II) modeset(0): EDID Version: 1.4
[397828.650] (II) modeset(0): Number of EDID sections to follow: 1
[397828.650] (II) modeset(0): EDID (in hex):
[397828.660] (II) modeset(0): EDID for output HDMI-2
[397828.666] (II) modeset(0): EDID for output DP-3
[397828.676] (II) modeset(0): EDID for output HDMI-3
[397828.917] (WW) modeset(0): Option "CustomEDID" is not used
[397870.768] (II) modeset(0): EDID vendor "DEL", prod id 16698
[397870.768] (II) modeset(0): Using EDID range info for horizontal sync
[397870.768] (II) modeset(0): Using EDID range info for vertical refresh
[397870.985] (II) modeset(0): EDID vendor "DEL", prod id 16698
[397881.227] (II) modeset(0): EDID vendor "DEL", prod id 16698
[397881.344] (II) modeset(0): EDID vendor "DEL", prod id 16698
[397882.361] (II) modeset(0): EDID vendor "DEL", prod id 16698
[398065.391] (II) modeset(0): EDID vendor "DEL", prod id 16698
[398065.572] (II) modeset(0): EDID vendor "DEL", prod id 16698
[398065.664] (II) modeset(0): EDID vendor "DEL", prod id 16698
[398067.535] (II) modeset(0): EDID vendor "DEL", prod id 16698
[398067.685] (II) modeset(0): EDID vendor "DEL", prod id 16698

Do I need to pass it to the kernel CMDLINE? I thought Xorg would be sufficient?

Added later 38 min 05 s:
Actually I can achieve the same like xfce4-panel --restart by just re-applying my panel profile, which again leads to my feature request https://forum.xfce.org/viewtopic.php?id=13091 and https://gitlab.xfce.org/xfce/xfce4-sett … issues/530 .

Last edited by Mo_B (Yesterday 10:43:47)

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