1. Please describe the problem:

When using kernel-6.15.3-200.fc42.x86_64 / Fedora 42 Workstation, the HDMI monitor never receives a signal (enters power-saving mode and turns off).

The following message comes up in journalctl kernel logs:

fedora kernel: [drm:parse_edid_cea.constprop.0.isra.0 [amdgpu]] *ERROR* EDID CEA parser failed

However when going back to Linux fedora 6.14.11-300.fc42.x86_64, the HDMI monitor works perfectly without the above kernel message.

In the display options in Workstation settings UI, the monitor appears enabled and working.  Toggling it on and off does not remedy the issue.  Nor does adjusting refresh rate or resolution.  If the primary displayport monitor is disabled and the secondary hdmi monitor is left enabled, 
it also does not remedy the issue.

The monitor itself acts as though no signal is received and enters power-saving mode (screen goes black, power led goes from white to amber.

Additionally and Interestingly enough, but perhaps not related, is if a virtual machine is started with a vfio-pci setup with a DisplayPort output from another GPU, the monitor also fails to receive a signal.


2. What is the Version-Release number of the kernel:

6.15.3-200.fc42.x86_64

3. Did it work previously in Fedora? If so, what kernel version did the issue
   *first* appear?  Old kernels are available for download at
   https://koji.fedoraproject.org/koji/packageinfo?packageID=8 :

Yes.  It works in 6.14.11-300.fc42.x86_64


4. Can you reproduce this issue? If so, please provide the steps to reproduce
   the issue below:

Yes.  Simply restart fedora and select the 6.15 kernel.  

5. Does this problem occur with the latest Rawhide kernel? To install the
   Rawhide kernel, run ``sudo dnf install fedora-repos-rawhide`` followed by
   ``sudo dnf update --enablerepo=rawhide kernel``:

Yes, with additional kernel errors logged:


kernel: amdgpu 0000:15:00.0: [drm] *ERROR* LTTPR count is nonzero but invalid lane count reported. Assuming no LTTPR present.
kernel: amdgpu 0000:15:00.0: [drm] *ERROR* dc_dmub_srv_log_diagnostic_data: DMCUB error - collecting diagnostic data
kernel: amdgpu 0000:15:00.0: [drm] *ERROR* Error queueing DMUB command: status=2
kernel: amdgpu 0000:15:00.0: amdgpu: [drm] *ERROR* EDID CEA parser failed

6. Are you running any modules that not shipped with directly Fedora's kernel?:

No


7. Please attach the kernel logs. You can get the complete kernel log
   for a boot with ``journalctl --no-hostname -k > dmesg.txt``. If the
   issue occurred on a previous boot, use the journalctl ``-b`` flag.

i do not see an attach button on this form.  ill try submitting first to see if it appears afterwards.

Reproducible: Always

Steps to Reproduce:
1.  Select 6.15 or rawhide 6.16 kernel
2.  Startup
3.  Observe HDMI monitor not receiving signal
Actual Results:
Above journalctl kernel messages appear.

Expected Results:
Monitor should function, with no kernel amdgpu errors

Additional Information:
$ glxinfo | grep -e OpenGL.vendor -e OpenGL.renderer
OpenGL vendor string: AMD
OpenGL renderer string: AMD Radeon Graphics (radeonsi, raphael_mendocino, LLVM 20.1.6, DRM 3.61, 6.14.11-300.fc42.x86_64)
$ lspci -n -n -k | grep -A 2 -e VGA -e 3D
15:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Raphael [1002:164e] (rev c9)
	Subsystem: Micro-Star International Co., Ltd. [MSI] Device [1462:7e12]
	Kernel driver in use: amdgpu


$ sudo ddcutil detect
Display 1
   I2C bus:  /dev/i2c-0
   DRM connector:           card1-HDMI-A-1
   EDID synopsis:
      Mfg id:               LEN - Lenovo Group Limited
      Model:                LEN Y27q-20
      Product code:         26094  (0x65ee)
      Serial number:        
      Binary serial number: 911365955 (0x36525743)
      Manufacture year:     2020,  Week: 9
   VCP version:         2.2

Display 2
   I2C bus:  /dev/i2c-4
   DRM connector:           card1-DP-1
   EDID synopsis:
      Mfg id:               LEN - Lenovo Group Limited
      Model:                LEN Y27q-20
      Product code:         26094  (0x65ee)
      Serial number:        
      Binary serial number: 911759921 (0x36585a31)
      Manufacture year:     2020,  Week: 15
   VCP version:         2.2


$ xrandr --current
Screen 0: minimum 16 x 16, current 5120 x 1440, maximum 32767 x 32767
DP-1 connected primary 2560x1440+0+0 (normal left inverted right x axis y axis) 600mm x 340mm
   2560x1440    143.91*+
   1920x1440    143.90  
   1600x1200    143.89  
   1440x1080    143.80  
   1400x1050    143.89  
   1280x1024    143.79  
   1280x960     143.86  
   1152x864     143.92  
   1024x768     143.87  
   800x600      143.83  
   640x480      143.85  
   320x240      142.05  
   1920x1200    143.89  
   1680x1050    143.88  
   1440x900     143.86  
   1280x800     143.84  
   1152x720     143.77  
   960x600      143.72  
   928x580      143.50  
   800x500      143.68  
   768x480      143.69  
   720x480      143.85  
   640x400      143.37  
   320x200      141.40  
   2048x1152    143.88  
   1920x1080    143.88  
   1600x900     143.93  
   1368x768     143.77  
   1280x720     143.67  
   1024x576     143.91  
   864x486      143.63  
   720x400      143.88  
   640x350      143.57  
HDMI-1 connected 2560x1440+2560+0 (normal left inverted right x axis y axis) 600mm x 340mm
   2560x1440    143.91*+
   1920x1440    143.90  
   1600x1200    143.89  
   1440x1080    143.80  
   1400x1050    143.89  
   1280x1024    143.79  
   1280x960     143.86  
   1152x864     143.92  
   1024x768     143.87  
   800x600      143.83  
   640x480      143.85  
   320x240      142.05  
   1920x1200    143.89  
   1680x1050    143.88  
   1440x900     143.86  
   1280x800     143.84  
   1152x720     143.77  
   960x600      143.72  
   928x580      143.50  
   800x500      143.68  
   768x480      143.69  
   720x480      143.85  
   640x400      143.37  
   320x200      141.40  
   2048x1152    143.88  
   1920x1080    143.88  
   1600x900     143.93  
   1368x768     143.77  
   1280x720     143.67  
   1024x576     143.91  
   864x486      143.63  
   720x400      143.88  
   640x350      143.57