Drm: mgag200. Video adapter issue with 5.4.0-rc3 ; no graphics

[John Donnelly]

Hi,

I am investigating an issue where we lose video activity when the display is switched from from “text mode” to “graphic mode” 
on a number of  servers using this driver.    Specifically  starting the GNOME desktop. 

This adapter is  Server Engines  Integrated Remote Video Acceleration Subsystem (RVAS)  and is used as remote console in iLO/DRAC environments.  

I don’t see any specific errors in the gdm logs or message file other than this:


mgag200 0000:04:00.0: remove_conflicting_pci_framebuffers: bar 0: 0x9b000000 -> 0x9bffffff 
mgag200 0000:04:00.0: remove_conflicting_pci_framebuffers: bar 1: 0x9c810000 -> 0x9c813fff 
mgag200 0000:04:00.0: remove_conflicting_pci_framebuffers: bar 2: 0x9c000000 -> 0x9c7fffff 

fb0: switching to mgag200drmfb from EFI VGA 
mgag200 0000:04:00.0: vgaarb: deactivate vga console 
fbcon: mgag200drmfb (fb0) is primary device 
mgag200 0000:04:00.0: fb0: mgag200drmfb frame buffer device 
[drm] Initialized mgag200 1.0.0 20110418 for 0000:04:00.0 on minor 0

The systems worked fine with  4.18  kernels  and a recent Linux  5.2.18 ;  The symptom first appears in 5.3.6. and onward.