Generic USB Display Driver Published For Linux - Allowing Nifty Possibilities With Raspberry Pi, Etc

[M@yeulC]

Did this get merged, BTW?

[raun0]

I am struggling with the use case here.

USB2HDMI adapters are less than $20 and they offload the decoding requirements so the Pi CPU wouldn't have to.

I have some generic USB2 display dongles from 5 or 6 years ago that have full kernel support still.

Could you link some? I want to test one! I never even realise that kind of thing exist. For quick look every dongle that I has found was only windows supported.

[oiaohm]

Diaplaylink v2 was open, DisplayLink v3 is not. The question is, what kind of hardware will this support? New hardware? Or could this be used for DisplayLink v3 devices?

The answer would be no with Displaylink v3 hardware as this would require Displaylink to open up their protocol compression and other things for mainline kernel include.

This seems interesting, as it could potentially turn any KODI tv box (or if implemented in Android, those cheap TV mini boxes) into a docking station for your Laptop or GNU-Linux running phone. Even if they don't support DP out over USB.

Its not any because it requires the device being the screen to have USB in device mode not host mode. I would like to see version of this that allows the screen to be in USB host mode and the provider being usb device mode as this would open up more combinations that could work.

nerdopolis as Julius states there will be existing hardware that can use this driver that does have a device mode and a screen output and upgradeable linux based software. Raspberry pi 4 has a USB 2.0 device hiding in it USB C socket for power so that in theory could provide 2 low refresh rate screen and that is good enough for the likes of Que cards for speakers and non animated slide show presentations where 1fps is fast enough. But this is not the only device out there that can be reconfigured.

[Julius]

This seems interesting, as it could potentially turn any KODI tv box (or if implemented in Android, those cheap TV mini boxes) into a docking station for your Laptop or GNU-Linux running phone. Even if they don't support DP out over USB.

[wizard69]

DisplayLink while nifty, is proprietary & closed source last I looked.
If this is open, then it would be a great way forward.

This is a big factor but I would also think this would simplify hardware in that there is no reason to switch to DisplayLink I/O and protocols. I see it as a big win for uncompromised low cost hardware.

[nerdopolis]

Diaplaylink v2 was open, DisplayLink v3 is not. The question is, what kind of hardware will this support? New hardware? Or could this be used for DisplayLink v3 devices?

[Happy Heyoka]

So in the end the point is to do exactly what USB Displaylink does?
Or the is the gadget driver some generic framebuffer concept?
I'm not sure I fully understand.

DisplayLink while nifty, is proprietary & closed source last I looked.
If this is open, then it would be a great way forward.

[oiaohm]

I am struggling with the use case here.

USB2HDMI adapters are less than $20 and they offload the decoding requirements so the Pi CPU wouldn't have to.

I have some generic USB2 display dongles from 5 or 6 years ago that have full kernel support still.

If you are wanting to experiment with different compression protocols and decoding ideas existing USB2HDMI adaptors don't cut it. Pi CPU does contain a GPU with video decoding ability. Yes this is only the first stage but in theory the pi could provide vaapi you have to start somewhere.

[caligula]

I am struggling with the use case here.

USB2HDMI adapters are less than $20 and they offload the decoding requirements so the Pi CPU wouldn't have to.

I have some generic USB2 display dongles from 5 or 6 years ago that have full kernel support still.

You could also ask why anyone would need a USB ethernet or serial gadget when there are cheap < $5 USB UART and USB ethernet adapters .

[caligula]

So in the end the point is to do exactly what USB Displaylink does?
Or the is the gadget driver some generic framebuffer concept?
I'm not sure I fully understand.

USB gadgets provide a programmable interface. You can basically turn any USB OTG device into a display. I know there are Displaylink devices but I can't figure out how to transform my SBCs into displays. Well I could use VNC over USB ethernet I guess.