Choppy image on Kubuntu 19.04 with Ryzen 2500U

[nicoco007]

I recently got a new laptop and finally got around to installing Kubuntu 19.04 on it. I tried running this script as I did on my old laptop (on which it worked flawlessly with Kubuntu up to 18.10, thanks for you great work!) and DisplayLink is able to find and show an image on my external monitor (an ASUS MB169B+, 1080p via USB 3.0) but unfortunately the image is very choppy, even when just the cursor is moving. The laptop screen itself stays smooth and there isn't an obvious reduction in peformance when the monitor is plugged in. CPU usage stays relatively low (reaches ~50% on one core when moving a window around on the external monitor).

Things I've tried:

• Update kernel to version 5.1.2 - driver 5.1.26 fails to compile
• Downgrade kernel to 4.19.43 and 4.18.20 - problem remains
• Downgrade driver to 4.4.24 - compiles only against kernel 4.18.20 and problem remains
• Follow what was done in Displaylink with AMD Ryzen 5 2500U GPU #180 - DisplayLink service no longer starts and the xrandr provider disappears
• Change the resolution to something under 1920×1080 - problem is less obivous but still present
• Install EVDI 1.6.1 on top of the default 1.6.0 - monitor is detected but screen is completely black with no cursor (I guess that's progress?) eventually got it to work but the problem remains

As mentionned in the title, my laptop has an AMD Ryzen 2500U APU with Vega 8 graphics.

Debug information:

--------------- Linux system info ----------------

Distro: Ubuntu
Release: disco
Kernel: 5.0.0-15-generic

---------------- DisplayLink info ----------------

Driver version: 5.1.26
DisplayLink service status: up and running
EVDI service version: 1.6.0

------------------ Graphics card -----------------

Vendor: amdgpu
i2c_amd_mp2
Subsystem: [Radeon
Inc.
VGA: Advanced Micro Devices, Inc. [AMD/ATI] Raven Ridge [Radeon Vega Series / Radeon Vega Mobile Series] (rev c4)
VGA (3D): 
X11 version: 1.20.4-1ubuntu3
X11 configs: /etc/X11/xorg.conf.d/20-displaylink.conf

-------------- DisplayLink xorg.conf -------------

File: /etc/X11/xorg.conf.d/20-displaylink.conf
Contents:
 Section "OutputClass"
    Identifier  "DisplayLink"
    MatchDriver "evdi"
    Driver      "modesetting"
    Option      "AccelMethod" "none"
EndSection

-------------------- Monitors --------------------

Providers: number : 3
Provider 0: id: 0x99 cap: 0x9, Source Output, Sink Offload crtcs: 4 outputs: 2 associated providers: 2 name:Unknown AMD Radeon GPU @ pci:0000:03:00.0
Provider 1: id: 0x63 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
Provider 2: id: 0x41 cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting

-------------------------------------------------------------------

Provider 2 appeared after I tried a few random things to fix the problem; it doesn't seem to affect anything at this point in time but it might be a good idea to figure out how to get rid of it.

Not sure if this is useful, but here's the output from the commands asked in #180:

$ cat /etc/X11/xorg.conf.d/20-displaylink.conf
Section "OutputClass"
    Identifier  "DisplayLink"
    MatchDriver "evdi"
    Driver      "modesetting"
    Option      "AccelMethod" "none"
EndSection

$ lspci | grep -i vga
03:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Raven Ridge [Radeon Vega Series / Radeon Vega Mobile Series] (rev c4)
03:00.7 Non-VGA unclassified device: Advanced Micro Devices, Inc. [AMD] Device 15e6

$ lspci -nnk | grep -i vga -A3 | grep 'in use'|cut -d":" -f2|sed 's/ //g'
amdgpu
i2c_amd_mp2

$ lspci -nnk | grep -i vga -A3|grep Subsystem|cut -d" " -f5
[Radeon
Inc.

I'm guessing it's something to do with the xorg configuration, but I have no idea where to start. Any ideas?

[Crashdummyy]

Hey Nico, any Solutions yet?
I am facing the Same Issue as you Running a Hp ENvy x360 with an Ryzen 2700u ( Vega 10 )

--------------- Linux system info ----------------

Distro: Ubuntu
Release: disco
Kernel: 5.0.0-17-generic

---------------- DisplayLink info ----------------

Driver version: 5.1.26
DisplayLink service status: up and running
EVDI service version: 1.6.0

------------------ Graphics card -----------------

Vendor: amdgpu
Subsystem: Ridge
[103c:8497]
SATA
VGA: Advanced Micro Devices, Inc. [AMD/ATI] Raven Ridge [Radeon Vega Series / Radeon Vega Mobile Series] (rev c3)
VGA (3D): 
X11 version: 1.20.4-1ubuntu3
X11 configs:

-------------- DisplayLink xorg.conf -------------

File: /etc/X11/xorg.conf.d/20-displaylink.conf
cat: /etc/X11/xorg.conf.d/20-displaylink.conf: No such file or directory
Contents:
 

-------------------- Monitors --------------------

Providers: number : 3
Provider 0: id: 0x56 cap: 0x9, Source Output, Sink Offload crtcs: 4 outputs: 3 associated providers: 2 name:Unknown AMD Radeon GPU @ pci:0000:04:00.0
Provider 1: id: 0x5dc cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting
Provider 2: id: 0x58a cap: 0x2, Sink Output crtcs: 1 outputs: 1 associated providers: 1 name:modesetting

-------------------------------------------------------------------

I couldn't get an Image to begin with, so I removed the .conf as suggested.

$ lspci | grep -i vega
04:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Raven Ridge [Radeon Vega Series / Radeon Vega Mobile Series] (rev c3)

$ lspci -nnk | grep -i vga -A3 | grep 'in use'|cut -d":" -f2|sed 's/ //g'
amdgpu

[nicoco007]

Not really, but I've come to the conclusion that it might be an issue with EVDI itself since I couldn't get it to work properly on Ubuntu 18.04, so I created another issue over on their tracker.

[Crashdummyy]

@nicoco007 Thanks a lot, I see you have the same Problems as I do ( like immense stuttering if only using the External Displays )

[Crashdummyy]

Hey @nicoco007 i don't know how this would work out on your end.
But when I use Wayland instead of X the stuttering is (almost) completely gone ;)

[nicoco007]

What's your setup? I'm just getting a black screen or straight up crashes when trying to use Wayland. I don't even see the Wayland options on a clean install of Ubuntu 19.04, I have to downgrade to kernel 4.18 to see it.

[Crashdummyy]

That's strange.
I'm just using the latest 19.04 with Linux Kernel 5.0.0.17.20

It uses GDM3 where you can turn on Wayland on the LogIn screen ( there is a Cog somewhere... )

[nicoco007]

Weird. I don't get a cog on 5.0.0-19-generic, and I doubt change from 17 to 19 made it disappear...

[nicoco007]

Nevermind, I must have done something wrong the first time because I just got it to work. Kind of weird it works so well since I'm pretty sure they don't actually support Wayland yet...

[nicoco007]

Unfortunately that doesn't seem work on Kubuntu, most likely because KDE Plasma doesn't fully support Wayland yet :(

I guess I'll just go back to Ubuntu, at least for the time being. nevermind, after trying it I remembered why I switched to KDE in the first place.

[Crashdummyy]

I wouldn't use Gdm3 either if it were not for the Touchscreen Experience 😆
No problems with displaylink on i3 :)

[legion49f]

I switched to Wayland and the framerate is around 50fps now

[Barabazs]

Closing this issue due to inactivity.

Please reopen this issue if it still persists.

[dkebler]

I have a related issue with vega10/rsyzen machine but opened a new issue here.
#621