Fedora 42 KDE Black Screen After Login (AMD iGPU)

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1

I’m on Fedora 42 on plasma KDE, and am experiencing the issue of having it black-screen after trying to log in for the first time. This black screen can sometimes disappear and I can get into the desktop, but sometimes it freezes indefinitely; a reboot can often fix this. I think there may be some relation to Consistent screen freezes after upgrading to F42 - #29 by gilbert-fernandes, but I’m not on GNOME, and my screen doesn’t appear to freeze after login; I do experience some case of text becoming buggy looking but pressing the text seems to fix that.

6.14.5-300.fc42.x86_64 (this happened on other earlier releases of 42)`

dnf list --installed | grep desktop 

abrt-desktop.x86_64                                  2.17.6-4.fc42                       <unknown>
desktop-backgrounds-compat.noarch                    42.0.0-2.fc42                       <unknown>
desktop-file-utils.x86_64                            0.28-1.fc42                         <unknown>
gsettings-desktop-schemas.x86_64                     48.0-1.fc42                         <unknown>
kf5-qqc2-desktop-style.x86_64                        5.116.1-3.fc42                      <unknown>
kf6-qqc2-desktop-style.x86_64                        6.13.0-2.fc42                       <unknown>
open-vm-tools-desktop.x86_64                         12.4.0-4.fc42                       <unknown>
plasma-desktop.x86_64                                6.3.5-1.fc42                        <unknown>
plasma-desktop-doc.noarch                            6.3.5-1.fc42                        <unknown>
sound-theme-freedesktop.noarch                       0.8-23.fc42                         <unknown>
xdg-desktop-portal.x86_64                            1.20.0-1.fc42                       <unknown>
xdg-desktop-portal-gtk.x86_64                        1.15.3-1.fc42                       <unknown>
xdg-desktop-portal-kde.x86_64                        6.3.5-1.fc42                        <unknown>

I am a bit new to Fedora, so have tried to provide as much context as I can understand may be applicable to troubleshoot this.

I have a 7900 XTX for a dGPU, but prefer to use my 9 7900x iGPU to save VRAM for LLM inference. From my looks I feel this is likely a AMD driver issue.

sudo dmesg | grep -i error  

[    4.557409] amdgpu 0000:12:00.0: [drm] *ERROR* lttpr_caps phy_repeater_cnt is 0x0, forcing it to 0x80.
[   95.205230] WARNING: CPU: 12 PID: 802 at ./include/linux/dma-fence.h:587 dma_fence_set_error+0x18/0x30 [amdgpu]
[   95.205512] RIP: 0010:dma_fence_set_error+0x18/0x30 [amdgpu]


vulkaninfo --summary 
 
GPU0:  
       apiVersion         = 1.4.305  
       driverVersion      = 25.0.4  
       vendorID           = 0x1002  
       deviceID           = 0x164e  
       deviceType         = PHYSICAL_DEVICE_TYPE_INTEGRATED_GPU  
       deviceName         = AMD Radeon Graphics (RADV RAPHAEL_MENDOCINO)  
       driverID           = DRIVER_ID_MESA_RADV  
       driverName         = radv  
       driverInfo         = Mesa 25.0.4  
       conformanceVersion = 1.4.0.0  
       deviceUUID         = 00000000-1200-0000-0000-000000000000  
       driverUUID         = 414d442d-4d45-5341-2d44-525600000000
       
GPU1:  
       apiVersion         = 1.4.305  
       driverVersion      = 25.0.4  
       vendorID           = 0x1002  
       deviceID           = 0x744c  
       deviceType         = PHYSICAL_DEVICE_TYPE_DISCRETE_GPU  
       deviceName         = AMD Radeon RX 7900 XTX (RADV NAVI31)  
       driverID           = DRIVER_ID_MESA_RADV  
       driverName         = radv  
       driverInfo         = Mesa 25.0.4  
       conformanceVersion = 1.4.0.0  
       deviceUUID         = 00000000-0300-0000-0000-000000000000  
       driverUUID         = 414d442d-4d45-5341-2d44-525600000000
3

Experienced a black screen of death recently when returning to the computer after sleep, going to try and downgrade mesa to see if it works following other threads I’ve read. Following this thread.

Also might try DRI_PRIME=1 and/or amdgpu.dcdebugmask=0x10 in the future if this doesn’t help and I can understand their expected effects better.