Disclaimer

The content of this blog is my personal opinion only. Although I am an employee - currently of Imagination Technologies's MIPS group, in the past of other companies such as 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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