M1S vu5s and vu8s + HDMI limitations

[mad_ady]

Hello,
I've looked over the wiki pages for the vu5s and vu8s:

https://wiki.odroid.com/odroid-m1s/appl ... _note/vu5s
https://wiki.odroid.com/odroid-m1s/appl ... _note/vu8s

and for vu8s it says:

If you activate the MIPI-DSI interface, the HDMI output function will be disabled automatically.
This is because HDMI and MIPI-DSI can NOT be used simultaneously due to system memory bandwidth limitations.

But the same warning is not present on the vu5s page. Is the same limitation present with vu5s and do you need to add the warning that the platform can't do dual displays (like M1), or would the vu5s work together with a HDMI display?
What about using a lower resolution with HDMI (e.g. connecting a VU7 via HDMI) - is the memory bandwidth limitation present at lower resolutions as well?

Thanks for the clarification!
Cheers!

[odroid]

Vu5S wiki page is still under construction. :
I've just added the same warning message to the Vu5S wiki page.

1920x1080 HDMI + 1280x800 MIPI-DSI couldn't work together in parallel on the M1S while the original M1 could use dual displays thanks to the faster DRAM bandwidth.
We may need to test more, for example, if 1024x600 HDMI + 1280x800 MIPI-DSI can work together or not.

My guess is that dual displays may be possible with a low resolution combination, but it is unlikely to be suitable for use in actual applications due to insufficient CPU/GPU performance.

[mad_ady]

Thanks for the clarification.
So - if both displays were to remain enabled (somehow), what should an end user expect? Screen tearing? Would it affect application performance because RAM bandwidth would be saturated?
My use-case for 2 displays involves mostly static images, so screen tearing would be acceptable. The HDMI display would display photos, the vu5s would display a browser dashboard. Right now, the 10 fps I get from the 3.5" display is plenty

[tobetter]

Thanks for the clarification.
So - if both displays were to remain enabled (somehow), what should an end user expect? Screen tearing? Would it affect application performance because RAM bandwidth would be saturated?
My use-case for 2 displays involves mostly static images, so screen tearing would be acceptable. The HDMI display would display photos, the vu5s would display a browser dashboard. Right now, the 10 fps I get from the 3.5" display is plenty

As of now, it's more than tearing...plenty random picture tiles on the screen.

[mctom]

The RK3566 datasheet does say...

Support two simultaneous displays(same source) in the following interfaces:

Maybe would have worked fine if they were displaying the same thing.

[mad_ady]

Ah, that might hamper my original plans... Thanks!