Raspberry Pi goes to white screen after login

On a Raspberry Pi 3+ with 32 GB sd card system loads and I can get ssh access to update packages through yast. All good there, reboot.
Using ssh to login I can start yast and add an ordinary user for regular non-root access.
Now if I try to log in directly at the console with the root or non-root user the screen goes completely white, with mouse cursor showing.
Dmesg shows a series of errors like this (about 20 or so):

  257.010080] [drm:vc4_bo_create [vc4]] *ERROR* Failed to allocate from CMA:
  257.010114] vc4-drm soc:gpu: [drm]                            V3D:  52560kb BOs (111)
  257.010132] vc4-drm soc:gpu: [drm]                     V3D shader:    268kb BOs (65)
  257.010142] vc4-drm soc:gpu: [drm]                           dumb:   3512kb BOs (5)
  257.010154] vc4-drm soc:gpu: [drm]                         binner:  16384kb BOs (1)
  257.010164] vc4-drm soc:gpu: [drm]                            RCL:      8kb BOs (1)
  257.010173] vc4-drm soc:gpu: [drm]                            BCL:      4kb BOs (1)
  257.010183] vc4-drm soc:gpu: [drm]                total purged BO:  21020kb BOs (226)

Thinking this might be related to lacking video memory allocated I examined the config.txt file in the EFI partition and found it was set to 32 so I increased this to 128 but the error persists. Any suggestions?

Hi
Ahh, CMA that jogged my memory, is the screen connected via HDMI or ribbon cable? If the latter, see https://en.opensuse.org/HCL:Raspberry_Pi3 “Known Issues”.

From a few releases back, there was also a kernel boot option for CMA memory, if connecting via HDMI then add your voice to this bug: https://bugzilla.opensuse.org/show_bug.cgi?id=1190737

I am using HDMI port, through an adapter to VGA monitor. I have added a comment to the bugzilla mentioned. Thanks.