Black screen w/ Vivo Y19C

[Yonle]

Device

• Mobile (Android 8.1)
• vivo 1820 (Y91C)
• aarch64
• Linux localhost 4.9.77+ #1 SMP PREEMPT Thu Jul 15 19:11:41 CST 2021 aarch64 Android (Not AVD)

MultiVNC version
2.0.7 (Play Store)

VNC server i'm connecting to

• VNC server vendor: tigervnc
• VNC server version: 1.10.0
• OS version: 8.1
• OS language: English

Describe the bug
When connected into VNC server, I only see a mouse with a black screen.

To Reproduce

• Open MultiVNC
• Connect to server

Expected Behavior
The remote screen shows up

Screenshots

Other VNC client (RealVNC viewer):

Logcat (Coming soon)

[bk138]

Thanks for the report @Yonle ! A few ideas:

• might it be that MultiVNC shows the upper left corner of the remote screen and one has to scroll down to see the other content?
• How would I be able to reproduce your setup? Is it termux?

[Yonle]

• might it be that MultiVNC shows the upper left corner of the remote screen and one has to scroll down to see the other content?

Does not seems that it's there.

• How would I be able to reproduce your setup? Is it termux?

It's in termux and reproduceable with the following command:

vncserver -geometry=1280x750 -securitytypes=none -zliblevel=0 :0

Can also done with Xvfb + x11vnc:

Xvfb :0 &
x11vnc --display :0 --forever

[bk138]

I see. Do you also get a black screen when connecting to another server that's not running on localhost?

[Yonle]

I see. Do you also get a black screen when connecting to another server that's not running on localhost?

Yes. I also tried to connect to my VPS VNC server, unfortunately no luck.

[bk138]

I see. Do you also get a black screen when connecting to another server that's not running on localhost?

Yes. I also tried to connect to my VPS VNC server, unfortunately no luck.

I have two ideas:

• Maybe it's the OpenGL drawing. Can you please try with https://github.com/gujjwal00/avnc and report if the issue is there as well (AVNC has similar OpenGL drawing to MultiVNC).
• We recently had to change something drawing related to fix Zooming broken on Android 12 #183, maybe this broke drawing for you. Can you give https://github.com/bk138/multivnc/releases/download/AndroidMultiVNC-2.0.0/multivnc-2.0.0.apk a try?

[Yonle]

Hi @bk138.

• At this point, AVNC works well as expected. Got no error at it.
• MultiVNC 2.0.0 also result the same black remote screen. Also tried with other VNC server.

[bk138]

Hi @bk138.

* At this point, AVNC works well as expected. Got no error at it.

* MultiVNC 2.0.0 also result the same black remote screen. Also tried with other VNC server.

No good idea at this point. It seems it's a combination of your device model and MultiVNC. You could try looking at the adb logs and scan for any errors, but that's about it :-/

[Yonle]

Hi @bk138.

* At this point, AVNC works well as expected. Got no error at it.

* MultiVNC 2.0.0 also result the same black remote screen. Also tried with other VNC server.

No good idea at this point. It seems it's a combination of your device model and MultiVNC. You could try looking at the adb logs and scan for any errors, but that's about it :-/

Well. See whenever i have a chance to get logcat error log.

[bk138]

Did a bit of googling:

• This phone's GPU is a PowerVR GE8320 according to https://www.naijatechguide.com/2020/07/vivo-y91c.html
• According to to https://www.notebookcheck.net/PowerVR-GE8320-Graphics-Card-Benchmarks-and-Specs.372646.0.html this is a Series8XE gen which supports OpenGL ES 3.2, which in turn supports glDrawTexfOES which MultiVNC uses 🤔

[bk138]

@Yonle you could also the last version of the 1.8 series give a try. If this works, the issue might be related to the new VNC engine.

[Yonle]

@Yonle you could also the last version of the 1.8 series give a try. If this works, the issue might be related to the new VNC engine.

And it actually doing it's job well

[bk138]

Interesting! In that case, an adb log from session setup from a recent MultiVNC version probably can shed some light on this if you're interested.