screen is black / off after suspend

za flag

my screen is not turning on after suspend.

I can see with the LED lights, the device is waking up.

The problem appeard with kernel "5.13.0-27-generic", but suspens is still working if I boot 5.13.0-21-generic.

What confuses me, I tested this on an external xubuntu installation (USB device), but suspend seems to work with 5.13.0-27.

System:    Kernel: 5.13.0-27-generic x86_64 bits: 64 Desktop: Xfce 4.14.2 Distro: Ubuntu 20.04.3 LTS (Focal Fossa) 
Machine:   Type: Laptop System: HP product: HP Laptop 15s-eq0xxx v: N/A serial: <filter> 
           Mobo: HP model: 86FD v: 99.42 serial: <filter> UEFI: AMI v: F.54 date: 11/26/2021 
CPU:       Topology: Quad Core model: AMD Ryzen 5 3500U with Radeon Vega Mobile Gfx bits: 64 type: MT MCP L2 cache: 2048 KiB 
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Picasso driver: amdgpu v: kernel 
           Display: x11 server: X.Org 1.20.13 driver: amdgpu,ati unloaded: fbdev,modesetting,vesa resolution: 1920x1080~60Hz 
           OpenGL: renderer: AMD Radeon Vega 8 Graphics (RAVEN DRM 3.41.0 5.13.0-27-generic LLVM 12.0.0) v: 4.6 Mesa 21.0.3 
za flag

I think the reason was boot option iommu=soft.

Because of a kernel bug, this option was required on battery mode:

This problem seems to be fixed, 5.13.0-27 is booting on battery without this setting and suspend is working as on my test system.


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