[HN Gopher] Using a Linux phone as a secondary monitor
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Using a Linux phone as a secondary monitor
Author : cunidev
Score : 144 points
Date : 2022-05-17 11:43 UTC (11 hours ago)
(HTM) web link (tuxphones.com)
(TXT) w3m dump (tuxphones.com)
| jrumbut wrote:
| 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.
| megous wrote:
| 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.
| bluedays wrote:
| Wish that I could use my iPad as a second screen. I'm even
| tempted to get a mac just for this feature
| spicybright wrote:
| 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 wrote:
| You don't even need dummy plugs with macOs now. You can use
| BetterDummy instead
| 867-5309 wrote:
| while you're at it, get another Tesla for a second windscreen!
| diffeomorphism wrote:
| > 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 wrote:
| 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 wrote:
| 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).
| bluedays wrote:
| Deskreen looks like the best solution out of all of the ones
| listed here.
| butz wrote:
| 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 wrote:
| 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
| cunidev wrote:
| Not only Miracast, but even Chromecast had >700ms latency in my
| experience :(
| squarefoot wrote:
| 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 wrote:
| 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 wrote:
| 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.
| bitwize wrote:
| The carriers wouldn't allow that, though. The carriers only
| permitted the iPhone _because_ Apple guaranteed it would be
| locked down.
|
| I am, of course, talking about the USA. I believe EU law
| forbids cellular carriers from being so thickheaded.
| xen2xen1 wrote:
| "distrubted database". What XDA isn't good enough?
| ur-whale wrote:
| Great hack.
|
| Would be even neater if I could stream music to the phone's sound
| system from my desktop.
| ben-schaaf wrote:
| Pulseaudio lets you turn any device into a speaker over
| Bluetooth or IP.
| aidenn0 wrote:
| Snapchat is good too, and already has Android clients
| radus wrote:
| *snapcast: https://github.com/badaix/snapcast
| aidenn0 wrote:
| grr... that was from my phone and autocorrect changed it;
| too late to edit now.
| seba_dos1 wrote:
| 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...
| KingVase wrote:
| Very nice setup. I wish it were possible with KDE Connect.
| askz wrote:
| 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 wrote:
| It is pretty easy to do that with X11 and VNC.
| bitwize wrote:
| 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.
| nocman wrote:
| > 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.
| yjftsjthsd-h wrote:
| What about X makes it fundamentally incapable of sending
| pixels off device at low latency?
| luke-stanley wrote:
| Actually it is possible to do low latency while using X
| server (for those not on Wayland), but it seems much faster
| to stream a video of the screen area than to use X protocol
| directly (which I have often used over SSH in the past to
| control another desktop system) - Xpra seems much faster to
| me. I've tried x11vnc too. Xpra is cool. Just my subjective
| experience, but proper benchmark stats would be cool to
| see.
| bitwize wrote:
| The X protocol is extremely chatty, does not compress
| images, and uses TCP. It's virtually impossible to make any
| sort of latency guarantees with that sort of protocol.
| Pipewire can use several compressed formats and the OP used
| UDP to stream the media off Pipewire to the remote display.
| yjftsjthsd-h wrote:
| Yeah, I know running X11 over the wire doesn't hold up,
| but that's not what's being done here with Wayland
| either; since we're locally grabbing pixels off the
| virtual display and _then_ flinging them over the wire
| via custom UDP protocol, X11 vs pipewire only matters for
| the initial handover.
| seba_dos1 wrote:
| The compositor may be able to transfer image data to
| PipeWire in zero-copy fashion, which may then be consumed
| by hardware video encoder without any copy on the path.
| I'm not sure whether you'd be able to do that using Xorg
| as display server.
| kache_ wrote:
| Imagine if you could do this with any phone tablet. Why can't
| you?
| askz wrote:
| you actually can, with vnc and sway
| https://github.com/any1/wayvnc/issues/7#issuecomment-6570922...
| silicon2401 wrote:
| does that with any phone, or just any tablet? It would be
| interesting to use old phones for media control or something
| diffeomorphism wrote:
| Any phone, tablet, fridge, toaster, ... that can run a vnc
| app.
| luke-stanley wrote:
| 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.
| megous wrote:
| 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)
| cunidev wrote:
| Tried Xpra ~2 years ago, but unfortunately it would not work
| for me, and it was Xorg-only at least at the time
| kzrdude wrote:
| Still is X-only.
| KerrickStaley wrote:
| 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.
| kzrdude wrote:
| Does this include using the phone as a touchpad? That would be
| cool and useful.
| vorpalhex wrote:
| "Unified Remote" for Android (paid, proprietary) works quite
| well for mouse control. No display sampling but it's not really
| needed.
| mhh__ wrote:
| 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.
| themodelplumber wrote:
| A little bit different but I hear the Sony VAIO VN-CX1 clearing
| its throat somewhere in the periphery...
| lordofgibbons wrote:
| 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.
| KerrickStaley wrote:
| Could you give a link to docs on that? I visited
| https://kdeconnect.kde.org/ but didn't see this feature
| mentioned.
| sudosysgen wrote:
| I dont know if its in the docs but it definitely works
| (just tested it)
| [deleted]
| mxuribe wrote:
| 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 wrote:
| You mean this https://invent.kde.org/network/kdeconnect-
| kde/-/merge_reques...? :)
| mxuribe wrote:
| Yay!!! :-)
| rcarmo wrote:
| 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 wrote:
| > 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.
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