Using a Linux phone as a secondary monitor

https://tuxphones.com/howto-linux-as-second-wireless-display-for-linux/

by cunidev • 4 years ago

172 64 4 years ago

tuxphones.com

ur-whale• 4 years ago

Great hack.

Would be even neater if I could stream music to the phone's sound system from my desktop.

ben-schaaf• 4 years ago

Pulseaudio lets you turn any device into a speaker over Bluetooth or IP.

aidenn02• 4 years ago

Snapchat is good too, and already has Android clients

michaelmrose4• 4 years ago

Tried this with an android client and experienced substantial latency despite working just fine between 2 computers in the same lan.

Mpd seemed to work better.

seba_dos12• 4 years ago

That's super easy already. You can make the phone act as a USB sound card, or you can use PulseAudio's network transparency (see https://puri.sm/posts/speak-to-me/), or you can broadcast an RTP stream, or you can use Bluetooth audio...

squarefoot• 4 years ago

That low latency is an impressive achievement, makes me want to attempt to convert all my old tablets to a real Linux install (no chroot jails etc), but the risk of bricking them is really high. I wish there was some tool to probe the hardware under Android, possibly against a distributed database, to know at least if the device is similar to a more known one (it could be the case among no name cheap Chinese tablets) and if there are chances of success before a blind attempt.

usrn• 4 years ago

Most SOCs have a mode you can put them into with just the hardware switches that runs firmware in the mask ROM which waits for a bootloader over USB. It's pretty hard to actually brick modern devices.

mschuster91• 4 years ago

Yeah, but most non-brand manufacturers don't release the tools, driver packages or the full firmware images at all - meaning you have to rely on questionable third party sites, hackers and leakers to obtain them to recover your device. I don't even want to know how many people ended up with malware from shoddy SEO-spam domains advertising Samsung's ODIN tool.

If Google had forced everyone to use the aboot boot loader and to allow rooting, we wouldn't be in this damn mess of people using all kinds of highly questionable stuff.

xen2xen1• 4 years ago

"distrubted database". What XDA isn't good enough?

imtringued• 4 years ago

I get 100-200ms including network latency to a faraway server that has no hardware for encoding or decoding video via webrtc in a browser with vp8 without even trying. Anyone who can freely choose their encoder and decoder including hardware acceleration should be well within 50ms on a local network.

In fact, the biggest problem for me isn't the lack of HW encoding, it is the lack of HW decoding because it makes 60fps videos on YouTube unplayable.

bluedays2• 4 years ago

Wish that I could use my iPad as a second screen. I’m even tempted to get a mac just for this feature

spicybright2• 4 years ago

There's definitely ways you can do that. Look into programs that use HDMI dummy plugs.

It's a little stub that plugs into an HDMI port trick the OS into rendering a separate screen. Then there are a lot of apps that let you display/interact with that virtual screen, usually through some kind of browser. Acts exactly like any monitor you plug in, regardless of OS.

It seems silly to need hardware for this, but it's a very clean/stable way to do this without mucking with config files or using weird hacks.

raihansaputra• 4 years ago

You don't even need dummy plugs with macOs now. You can use BetterDummy instead

867-5309• 4 years ago

while you're at it, get another Tesla for a second windscreen!

diffeomorphism2• 4 years ago

Wish that I could use my iPad as a second screen.

No wishing necessary. Before apple sherlocked the idea with sidecar there have been multiple apps that let you do that and are (somewhat) cross-platform (Luna display, duet, ...). These apps are still around and much better than the apple one for specialized use cases like art, they cost money though.

Or, if you don't need high speed, just go the simple vnc route, e.g.

https://kbumsik.io/using-ipad-as-a-2nd-monitor-on-linux

ant6n• 4 years ago

Apparently u can do that on windows with something called Duet (see https://youtu.be/PIKB0sJg0_Ij - the video mentions another software ad well)

bentcorner• 4 years ago

I use Deskreen to attach an Android tablet to my PC. All it requires is (I think) a modern browser for the mobile device (and you currently need an hdmi dummy plug on the PC).

bluedays2• 4 years ago

Deskreen looks like the best solution out of all of the ones listed here.

askz2• 4 years ago

I actually achieved the same, with benefits.

The hack is here: https://github.com/any1/wayvnc/issues/7#issuecomment-6570922...

Benefits are: two way interaction :)

throw93232• 4 years ago

It is pretty easy to do that with X11 and VNC.

bitwize4• 4 years ago

No. It's not. Fast video playback and low latency was a requirement, and you can't do that over the wire with X11 or VNC. Pipewire is the solution for this.

This is why SirCmpwn was right, and the anti-Wayland crowd needs to just shut up. Wayland+Pipewire is the future of remote desktop. Together they solve issues X11 by its nature cannot solve.

yjftsjthsd-h2• 4 years ago

What about X makes it fundamentally incapable of sending pixels off device at low latency?

nocman• 4 years ago

the anti-Wayland crowd needs to just shut up

I think telling people to shut up is a fast way to shut down valuable discussion. We can have good discussions about the value of particular technologies without being uncivil. Having strong opinions makes it easy to be unkind (especially online). I admit I also struggle with this. I think everyone could dial it down a bit from time to time.

michaelmrose4• 4 years ago

the anti-Wayland crowd needs to just shut up.

Maybe there wouldn't be a substantial antiwayland crowd if wayland proponents hadn't started saying that when wayland was an impractical mess years from being ready back in 2015-2017

Offering a superset of functionality in a prominent option without major downsides might have worked too.

At least it would have worked better than offering limitations and telling people to shut up and deal with it.

kache_• 4 years ago

Imagine if you could do this with any phone tablet. Why can't you?

askz2• 4 years ago

you actually can, with vnc and sway https://github.com/any1/wayvnc/issues/7#issuecomment-6570922...

silicon2401• 4 years ago

does that with any phone, or just any tablet? It would be interesting to use old phones for media control or something

mxuribe2• 4 years ago

This is great!

In my mind, i wish for KDE Connect to eventually evolve to enable something like this...KDE Connect is already a wonderful piece of software!

ognarb• 4 years ago

You mean this https://invent.kde.org/network/kdeconnect-kde/-/merge_reques...? :)

mxuribe2• 4 years ago

Yay!!! :-)

rcarmo• 4 years ago

I like the UDP approach. I tried doing something similar to multicast video streams to Raspberry Pi 1s quite a while ago (back when it was impossible to run a modern browser on them and we wanted live dashboards across the building), and it can be very efficient.

thomond• 4 years ago

Virtual display handling: creating a fake video output. On Xorg, some GPU-specific hacks exist (probably Intel-only)

Nvidia users are out of luck in my experience.

luke-stanley2• 4 years ago

I didn't see Xpra mentioned, but Xpra does desktop and window streaming with fast video encoding using H.265 (or H.264 and others options), and it has an experimental UDP transport - though I haven't needed it yet. In the Windows world, gamers use Parsec which matches those two network transport and encoding design decisions (which I am sure are the right direction).

To use Xpra as part of a secondary monitor solution, you might need to define a "dummy" window region for it, and I suspect X server can be configured to allow this but I don't know how yet.

I'm interested in any solutions for Linux secondary monitor devices too, especially more simple ones.

Edit: kbumsik link below uses xrandr to add a new display region and then uses x11vnc with a "clip" argument. I couldn't see such an argument for xrandr.

cunidev2• 4 years ago

Tried Xpra ~2 years ago, but unfortunately it would not work for me, and it was Xorg-only at least at the time

kzrdude2• 4 years ago

Still is X-only.

megous2• 4 years ago

This would work nicely on Pinephone, because it has very efficient accelerated decoding of H.264 codec. gstreamer using kmssink consumes very little power decoding H.264 video. It would likely run at ~2W with display on, so for about 5 hours on battery (at reasonable screen brightness)

butz• 4 years ago

What about standard, probably proprietary, solutions, like Miracast ("Wireless Display")? I wanted to use my old tablet with Windows as secondary monitor, but no luck when running Linux on primary PC. Best option is only mirroring desktop with GNOME Network Displays.

It would be great if there would be out of the box support for wireless displays on Linux.

samstave• 4 years ago

Im surprised Figma doesn't allw for this... only because their app dev kit with phone mirroring desktop is pretty sweet... I could see how it coud be adapted for this purpose

cunidev2• 4 years ago

Not only Miracast, but even Chromecast had >700ms latency in my experience :(

KerrickStaley2• 4 years ago

A related idea I had a while ago:

I think it'd be cool if you could use a cell phone as a mouse. You'd have a mount that holds the back of the phone slightly off the table, and the phone would track its position using the IMU and maybe motion tracking with the camera. The phone display could show a subregion of the monitor and you could click by tapping the phone screen.

themodelplumber• 4 years ago

A little bit different but I hear the Sony VAIO VN-CX1 clearing its throat somewhere in the periphery...

lordofgibbons• 4 years ago

You can already do this with KDE Connect on your phone. And you don't need to be running KDE for it to work on your desktop - it works with Gnome too.

KerrickStaley2• 4 years ago

Could you give a link to docs on that? I visited https://kdeconnect.kde.org/ but didn't see this feature mentioned.

kzrdude2• 4 years ago

Does this include using the phone as a touchpad? That would be cool and useful.

michaelmrose4• 4 years ago

Yes it also does text input including special keys, multimedia controls, app specific controls like Netflix and support for windows and Linux.

mhh__• 4 years ago

Forget mouse, I want to use a phone as a computer. I think the only hardware you can buy for less than a thousand dollars with arm SVE support is a phone, would be nice to just boot into debian seamlessly and run a test suite.

vorpalhex• 4 years ago

"Unified Remote" for Android (paid, proprietary) works quite well for mouse control. No display sampling but it's not really needed.

KingVase• 4 years ago

Very nice setup. I wish it were possible with KDE Connect.

jrumbut• 4 years ago

Linux phone is getting so exciting! I wish there was a way to dual boot or have something like a live CD to get into it in a low risk way.

megous2• 4 years ago

There's a way to multi-boot: https://xnux.eu/p-boot-demo/ (using a Pinephone bootloader)

You can also multi-boot using kexec (using Linux to boot other Linux image) or just by booting into initramfs that has a GUI program for selecting how to continue boot (which root filesystem to start from), etc.

follower• 4 years ago

If you haven't already checked it out, I'd suggest investigating use of `evdi` ("Extensible Virtual Display Interface") for the virtual display aspect of this:

* https://github.com/DisplayLink/evdi

* https://github.com/rhofour/evdi-vnc

Using a Linux phone as a secondary monitor

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