The content of this blog is my personal opinion only. Although I am an employee - currently of Nvidia, in the past of other companies such as Iagination Technologies, MIPS, Intellectual Ventures, Intel, AMD, Motorola, and Gould - I reveal this only so that the reader may account for any possible bias I may have towards my employer's products. The statements I make here in no way represent my employer's position, nor am I authorized to speak on behalf of my employer. In fact, this posting may not even represent my personal opinion, since occasionally I play devil's advocate.

See http://docs.google.com/View?id=dcxddbtr_23cg5thdfj for photo credits.

Friday, May 13, 2016

touch Device List

touch Device List: "GeChic On-Lap 1502 Ilitek, 10 Point, USB"

Learning the hard way that, although my GeChic external touchscreen display plugged into my MacBook and seemed to work, that the MacBook becomes unstable.

The video works fine.

The touch works at first - perhaps not the full multitouch that the GeChich is capable of, but at least in mouse emulation.

Unfortunately, after a few minutes - not even minutes of use, but minutes of just leaving it idle - whenever I touch the GeChic screen, the MacBook does a funny-not-quite-a-crash, with the upshot being that I am logged out and have to reenter my password to get back in.

It appears  that problems with touch on Macs are well known. “Touchscreens: iOS = Yes, OS X = No!"

The company Touch Base seems to have specialized in providing touch screen drivers for Macs, with a Unified Pointer Device Driver (UPDD).  Quite expensive. Like, 150$.  Well, at least the GeChic is on their supported touch device list.

Damn! I wish I had known this before wasting a few hours.  Strangely, many GeChic users report success with their Macs.

Knowing this does not excuse Apple's software.   If they do not support a device, she should say so - they should not support for a while, and then misbehave.

CONJECTURE: I think that the problem may be a I/O buffer overflow - not necessarily the "accessing memory beyond the limits specified by software", but the "too many I/O device inputs, the I/O buffer gets full and events have to be discarded, MacOS gives up after a while".

Why this suspicion?:  after I remove my finger from the GeChich touchscreen, the mouse cursor immediately goes to the upper right hand corner of the display, where it appears to "tremble".   I have seen that sort of thing with I/O devices that are constantly sending output, e.g. constantly reporting a position even when there has been no movement.

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External touch screen | Apple

External touch screen | Apple:


I wasted a few hours trying to use my GeChic 1502I external touchscreen with my MacBook.

The video works, no drivers.

The touchscreen works at first.  But after a few minutes, any touch makes the MacBook do a funny not-quite-a-crash --- all screens go dark, and I have to re-log in.

---+ DETAIL:

I just connected my GeChic On-Lap 1502I 15.6" Full HD IPS Panel 10-point Projected Capacitive Portable Touchscreen Monitor to my MacBook Pro.

Why?  I wanted a touchscreen to run my "UIX ButtonPad" app.   

I had been using Duet Display to give me an external touchscreen for my MacBook using an iPad mini. Earlier the Quadro app on iPhone/iPad, which provides only the Button Pad functionality and is not a full external display.  But I wanted features missing in Quadro, so I wrote my own. Running it all on the laptop was easier than creating a hybrid app split between laptop and touchscreen phone or tablet. I can use a phone or tablet as an external touchscreen using remote display apps like Duet Display  or Avatron Air Display 

Duet Display  worked when it worked, but suffered problems like losing connections, especially when the iPad screen locked. I have my screen lockout time set very low, like 30 seconds.

+: Plus, I had this big external GeChic 1502I touchscreen, dating back to before I used Apple iPads and Duet Display. It's bigger than any iPad at the time of writing, even the 12.9" iPad Pro.

++, I really miss having a touchscreen device as my main laptop, so I will probably switch back to a Windows Surface, Surface Pro, or Surface Book.  And I wanted my UIX ButtonPad app to work when I give up on Apple MacBooks.

+++ I can supposedly use my Surface as an external touchscreen display for my MacBook.  (Haven't tried but software seems to be out there - VNC if nothing else.) Vice versa, although of course the MacBook isn't a touchscreen - but I can imagine Surface->MacBook->Duet->Tablet.

++++: Plus, I have several old Android tablets (freebies from company and techcons), and a few old Android phones.  I would like to be able to deploy touchscreen UIX ButtonPads onto these devices as well.

DISAPPOINTMENT: Due Display doesn't run on my old iPad Classic. Needs a more modern version of iOS.  Must investigate jailbreaking or XNU - otherwise these old IOS devices are just e-trash.

BOTTOM LINE: hybrid apps split across systems are a bit harder; remote display and touchscreen almost eliminate need.  (Hybrid apps might be more elegant than remote display. But first must code them up.  Hmm... I wonder if one could create a remote display app that could then be "locked" to run only a single app on that display?  Display-locked apps?  App-locked displays? I don't like limiting choice, but I can understand reducing interactions.)

PLEASANT SURPRISE:  I mainly wanted to use my UIX ButtonPad app on a touchscreen, but since Duet Display was acting up I found that it is actually quite pleasant to use on a non-touchscreen mouse and pointer system.  You park your mouse on your primary big button, and just click.  Not quite as pleasant as a touchscreen, but nicer than a WIMPy GUI on a big multi-display system. Possibilities in mapping keyboard shortcuts and mouse/trackball buttons to "big buttons" on the ButtonPad.


But...  I started this blog entry not to describe UIX ButtonPad, but to record notes about using external touchscreens like my GeChic 1502I on a Mac.  

My system: MacBook Pro 15" mid-2014, 16GB RAM, NVIDIA GeForce GT 750M 2048 MB). After connecting the GeChic, I have 3 external monitors:  30" NX-VUE30, 2560x1600, connected using HDMI; 24" Acer X243W, 1200x1920, connected by a USB display adapter (Diamond BVU195 DisplayLink); and the GeChic 1502I, 15", 1920x1080.   For a total of 4 displays, with the Retina display on the MacBook (2880x1800).  

(Even before the GeChic, I tried to have another 24" 1920x1200 display using a USB display adapter - however, this had major problems on the Mac (worked on Windows 7), so I gave up on *that* extra display.  Since the GeChic now works as a 3rd external display, I may revisit adding yet another 1920x1200 display, since I have several dating back to my last windows systems, before I switched to Apple, and before I started using 30" displays as my primary display rather than 24". Perhaps Apple has fixed their software - the problems were pretty obviously driver memory allocation.)

I have used this GeChic display frequently with Windows machines, with no problems. Obviously, there were problems, albeit minor, connecting it to the MacBook - hence this post, which serves as notes for myself, and may help somebody else.

It is obvious that Apple Mac support for multiple, external, displays and touchscreens is less mature than Windows.  The MacBook problems remind me of problems I had with Windows circa 1999-2002, i.e. in the past century.

The first problem was connectors: 

The GeChic has micro HDMI and mini-VGA inputs.   I have used it in the past via the "normal" HDMI to micro-HDMI cables, both from GeChic, and similar cables that I bought at Frye's or Best Buy;  and via the mini-VGA input, which is aa bit harder to find.

My 30" display was using the only HDMI port on the MacBook.   

Using DisplayLink and HDMI simultaneously on the MacBook has not worked well in the past.

Connecting a second USB display adapter has not worked well in the past.  Besides, I still need connect MacBook--USB-->BVU195--DVI--> ... to the GeChic, mini-VGA or micro-HDMI.

In my kit of cables and adapters, I had I mini-DisplayPort to DVI adapter, and  DVI to HDMI adapter, as well as my HDMI to micro-HDMI cables.   So I hooked that up:




DisplayPort-to-DVI adapter


DVI-to-HDMI adapter


micro-HDMI port

GeChic 1502I

This worked (a bit to my surprise).  And I have not yet seen the display memory overrun problems that plagued my past attempts to have a 3rd external display on my MacBook.  (Possibly because the GeChic has fewer pixels.)

After much screen blanking and resetting, the MacBook came up.

Also connected: external DCIN for the GeChic (USB caable), aand USB for the touchscreen interface.

At first I wanted to use the GeChic upside down, because the cabling was easier than way. The MacBook understood this, after the usual hassle of having to rotate the display.  (Side note: I wish that more external displays could rotate locally, as opposed to depending on software on the PC.)

Things seemed good, until I started trying to use the GeChic touchscreen.

First problem:  if my big 30" display was the "main" monitor for the MacBook, touching the GeChic moved the cursor on the big display, not on the non-mirrored display extended to the GeChic.

Second problem: the GeChic was upside down.  Rotating the display in the Mac preferences rotated the display - but not the touchscreen.    I could not find any way to rotate the touchscreen on the MacBook.

Third problem:  in these configurations the MacBook kept - not exactly hanging or crashing, although I wonder if something almost as bad was happening.  The first two or three touches worked, but then the MacBook blanked all screens, and logged me out.  I don't THINK it crashed or rebooted, but it might as well have.   

So I gave in and turned the GeChic rightside up, and rearranged the cables to reach.

Given this, it seems to be working okay.  So far.

... Nope.  I just tried touching the GeChic screen, and the same screen blank / must type password and log back in problem occurred.   It was working for a while - I could move windows around by touch, etc. -  but has stopped working.

When I thought that all was working okay, I was going to pontificate on how I have never seen such problems with Windows - somehow windows managed to recognize that the touchscreen and display came from the same device.  But not Mac.

I tried connecting the GeChic via HDMI, and the 30" display via the DisplayPort-DVI-HDMI 2 adapter kluge.  This may have worked - the MacBook did not do that funny not-quite-a-crash when I touched the GeChic.  But the 30" monitor could not be driven at full resolution across DVI.

I happened to have with me my home Thunderbolt/DisplayPort-to-dual-DVI+USB adapter. No avail - still got the funny not-quite-a-crash when I touched the GeChic.

Thinking, I wondered if the problem might be that the GeChic touchscreen USB connection was being routed through a USB hub (an IOGear 7-port USB 2.0 hub).  Perhaps there is some sort of ID from the GeChic USB that can be correlated to a similar ID on the HDMI input, that somehow got filtered by the external USB hub.  Seems unlikely, since the Mac probably has an internal USB hub inside its case.   But I tried it anyway - connecting the GeChic USB touchscreen output directly to the MacBook.     Failed first try, using a thin standard USB A to microUSB cable.   Switched to the heavier 2 standard USB A to microUSB cable that GeChic provided.

... Success.  So far.  15 minutes. ... Nope - after a while, touch the screen and the MacBook does that funny not-quite-a-crash again.

(At least I didn't lose the notes I have typed into this blog.)

(Does anyone at Apple realize how annoying it is that display preferences ungathers every time the display configuration changes?  Why not put a gathered window on each?)


Finally, I did what I should have done first thing: I plugged the GeChic into my MacBook by itself.  No other displays.  Same symptoms.

I was misled by it "almost" working - by the display working immediately, and by the touchscreen working at first -- but then producing "not quite crashes" later.

I was misled by my familiarity with Mac multi-display problems and workarounds.  I wasted time working around incorrect guesses as to the root cause.

Plus, I was misled by my windows experience, where I have plugged in any number of touch devices - Wacom tablets, Cintiq, etc. - with no problem.  Not so for Apple, apparently.

I had already googled GeChic and Mac.  I was misled by reports that it worked; also, GeChic themselves said that it worked.   Later googling, after wasting all of that time, reveals that Macs are notorious bad at touchscreens: Apple's attitude seems to be "iOS=>touch, Mac=>no touch".   There are third party companies that provide $$$ Mac touchscreen drivers/

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