[Toybox] Phone docking stations for general purpose computing.

Rob Landley rob at landley.net
Mon May 18 21:03:27 PDT 2020


On 5/17/20 9:03 PM, David Seikel wrote:
> On 2020-05-17 20:42:05, Rob Landley wrote:
>> Hey Elliott, USB-C to HDMI adapters are going for $5 now. If I grabbed something
>> like https://www.ebay.com/i/312982429778 or https://www.ebay.com/i/302957153131
>> or any of the dozen others, and plugged that and my pixel 3a into the same usb-c
>> hub, could I get the display on my TV and if so what would I need to do?

The reason I asked "could I get the display on my TV" when forwarded through a
router is I knew the answer might not be "yes".

>> Next question: ARE there any usb-c hubs, and if so what keyword should I be
>> looking for to find them? All the hubs seem to be "USB-C to 4 USB-A" splitters.
>> so far. (It's like trying to find a gigabit ethernet switch in 2005: it's all
>> one uplink port and the rest is 100baseT.)
> 
> The big problem vith that is that not all USB-C is created equal. 
> Specifically, not all of them support video out.

"Simple cheap thing is still a hack, does not actually work." Got it.

According to https://en.wikipedia.org/wiki/Mobile_High-Definition_Link there's a
packet-based translation of HDMI that does 8K 3D nonsense in its new versions,
so getting a signal you can encapsulate as data and forward through a router for
bog standard 1080p should not be brain surgery. And yet...

A $5 pi zero can do vnc maintaining its own framebuffer for HDMI output. I know
this CAN be done, and done cheaply, and could be supported out of the box by
phone hardware. The question is when/if _will_ it be. (And if the easiest answer
is just "make an adapter out of a pi zero and sell them on etsy", FINE.)

Sigh. I keep TRYING to get people to steal my ideas and they NEVER DO. Heck,
half of
https://lists.linuxfoundation.org/pipermail/celinux-dev/2010-January/000292.html
still isn't done yet, meaning _I_ still have to do it. But then that's a chronic
complaint with me:

  https://landley.net/notes-2017.html#06-01-2017
  https://landley.net/notes-2019.html#14-01-2019
  https://landley.net/notes-2019.html#22-07-2019

I will fully admit to having gotten bitter about it:

  https://landley.net/notes-2020.html#15-05-2020

I don't know how to do this. I don't want to do this. I'm not qualified to do
this. And yet nobody else is doing it. Time to grab another rock and hit things
with it until I jiggle the right bit...

> For example - My Motolora Z has a USB-C, and is compatible with the
> Motorola Moto Mod system (add on hardware system that clips hardware
> extensions onto the back magnetically).  I can plug HDMI and USB keyboard
> / mouse into that, but not using the USB-C that is on the phone itself. 
> I have to use the USB-C that is on the Moto Mod developers kit, which is
> a Moto Mod with three USB ports, two USB-C and one micro B.  The HDMI
> comes out of one of those extra USB-C, but only using a hacked up Moto Mod
> firmware.  No video is available on the phones own USB-C, so I use that
> for the keyboard / mouse.  I plug the lot into my KVM.

Look, I just want this 5 year old hack but going the other way:

  https://www.raspberrypi.org/forums/viewtopic.php?t=127971

Although "ability to watch youtube videos on the big screen" would be darn nice
too, because that comes up surprisingly often.

> A powered hub that can supply power to the phone while you spend all day
> developing on it would also be useful.

That was part of my original 2013 talk, yes. And before that, I blogged about it
in 2010:

  https://landley.net/notes-2010.html#09-10-2010

And THAT said I'd been whingeing on about the topic since 2002. It would just be
nice if at some point the future actually ARRIVED.

> Another option for getting video out of a phone is Chromecast via WiFi. 
> That's what I use to give Google Daydream VR demos, so I can watch what is
> on the screen of the phone strapped to someone elses head.

Sure. Modulo that costing $35 instead of $5, needing a wireless hub between the
two of you (Fade has one, it doesn't do point to point from a phone for some
reason and was VERY unhappy that her apartment wireless had a login screen for
new devices) plus the inherent security and bandwidth constraint issues of
wireless keyboard and display in high density urban environments. (When I go to
UT I can't associate my laptop with my phone because the wifi is too overloaded
for them to find each other sitting 6 inches apart, I have to use a USB cable.)

But yeah, I was already saying "or chromecast" when ranting about this 5 years ago:

  https://lkml.org/lkml/2015/4/8/772

>> What's  useful is teaching new systems to have a "general purpose computing
>> mode" (in a container or whatever) that can plug the phone into keyboard, mouse,
>> and big display, and having THAT instead of having a PC means you are not a
>> second class citizen but a full-fledged developer. The "docking station" to give
>> a phone a real screen, keyboard, and mouse is a usb-c hub, usb mouse and
>> keyboard, and a $5 hdmi adapter, which is all cheap generic and (eventually)
>> ubiquitous.
> 
> There might be ubiquitous USB-C gadgets, but it'll be the return of Plug
> and Pray to see if you are lucky enough to have the correct set of
> gadgets that will talk to each other in the way you want.

Windows 98 couldn't do hotplug. (They added half-assed USB support in "second
edition", I.E. service pack 1). The first round of USB-C->USB-A adapter cables
could physically fry your hardware. "Oh no, new thing isn't as polished and
generic as existing thing, it is therefore doomed, stay with the old, stay with
the oooooold..."

I do not see any conceptual blockers that would make any new vendors ship the
older stuff ever again, beyond churning out more units on existing lines to
amortize the setup costs before inevitable retooling. Therefore, the old stuff
is an installed base that should peak and decline, but the new stuff should
continue to ship additional units in quantity for the foreseeable future with
possible backwards compatibility to "64 bit c99 software can target this, usb-c
connectors can plug into it" maybe even 20 years from now. (Which is "forever"
in computer terms. The event that obsoletes this is a black swan.)

> On the plus side, once the hardware is sorted, things just work.

Um... yes?

> I didn't have to teach my phone about external mice or keyboards.

USB mice and keyboards are 22 years old.

Look, I'm trying to ask "from here, what's the path of least resistance for
water to flow downhill to the sea". I'm pretty sure it's through 64 bit hardware
becoming ubiquitous and through usb-C becoming ubiquitous, to the point they
cycle out everything else and THIS NEW stuff becomes the cheap surplus available
in volume getting repurposed by 12 year olds. If that's the future I should be
modeling, trying to retrofit AOSP support for older hardware (as lineageos seems
to be doing) does not significantly advance my goals.

But keyboard+mouse need hub, video adapter on par with those (in cheapness, even
the very underprivileged can save up for a $5 part) only currently works (when
it does) WITHOUT a hub. Needs hub vs excludes hub is a conflict needing to be
resolved. How does that get resolved?

  https://www.youtube.com/watch?v=mmdVqCNev6Q#t=56s

Rob

P.S. The world has so many HDTVs that people are already fishing small and
medium sized ones out of the trash, and as solar panels and batteries continue
to follow https://en.wikipedia.org/wiki/Swanson%27s_law downwards (it's like
Moore's Law but the 50% price drop is every 5 years instead of every 1.5 years)
people who don't have running water or indoor toilets will have _some_
electricity in 5-10 years, and every
https://www.amazon.com/24000mAh-Waterproof-Portable-Compatible-Smartphones has
USB power outlets. Given that 100 watt solar panels are selling for $25 in
quantity 1 https://www.alibaba.com/countrysearch/CN/100-watt-solar-panel.html,
that's about $6 in 10 years. A 30 inch LCD draws 60 watts today and the charger
that came with my pixel 3a is rated at 18 watts. A USB battery pack that can
charge my phone  at Target. Or, you know, find a used tablet with a bigger
display built in and then EVERYTHING is DC and usb powered and there's no
inverters anywhere, and maybe that's the answer, but "phone is in pocket" is
less friction than "tablet must be carried", and exporting the phone display to
a bigger one is an unmet need I'm chewing on. It's clearly a thing people take
for granted that we'll do in the future:
https://www.youtube.com/watch?v=9E9bscLGTAA#t=3m10s



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