Created attachment 144122 [details]
dmesg

After updating to Xubuntu 19.04 I started having problems with the screen saver
feature. After a request for the monitor to go into power saving mode I am
unable to recover the system. When the monitor turns on again I get the last
image shown but I cannot move the cursor, nothing on the screen is moving,
everything is frozen and I cannot use ssh to access the machine.

Later I discovered that I could access the computer using ssh before I let the
monitor enter power saving mode and I was then able to save a copy of dmesg.

As soon as the monitor is turned off by the system the crash happens:

[ 2674.166451] general protection fault: 0000 [#1] SMP NOPTI
...
[ 2674.166530] RIP: 0010:dce110_vblank_set+0x4f/0xa0 [amdgpu]

with the last 5 entries of the call trace:

[ 2674.166624]  dal_irq_service_set+0x4c/0x90 [amdgpu]
[ 2674.166687]  dc_interrupt_set+0x24/0x30 [amdgpu]
[ 2674.166753]  dm_enable_vblank+0x2a/0x40 [amdgpu]
[ 2674.166768]  drm_vblank_enable+0xe2/0x130 [drm]
[ 2674.166781]  drm_vblank_get+0x92/0xb0 [drm]

I was using the Oibaf PPA both before and after I updated to Xubuntu 19.04.
I tried to use the kernel v5.1-rc7 from the Ubuntu mainline:
https://kernel.ubuntu.com/~kernel-ppa/mainline/

My linux command line:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash radeon.cik_support=0
amdgpu.cik_support=1 amdgpu.dc=1"