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Re: Convergence and Displaylink for external monitor

 

Hi Marco,


On 07/23/2015 11:18 PM, Marco A. Harrendorf wrote:

> Is this pure coincidence or does this mean that the new
> convergence phone from BQ will also make use of Displaylink to
> support the convergence feature on an external screen and thus
> Displaylink changed their mind ;-)?

No ;)


> What kind of connection to an external screen will the new
> convergence device use?

It will use MHL, to essentially make the GPU output a HDMI signal via
the USB port.


> Can we expect that the BQ 4.5 / 5 phones will also support
> Displaylink in the future, so that the convergence feature will
> also work with them? Or do they have not enough computing capacity
> to run an Ubuntu desktop?

That fully depends on the driver situation and if Mir will support it.

As far as I know, using a DisplayLink adapter would be the worst
solution possible. These devices have hardly any intelligence, they
just accept raw framebuffer data via USB and output it to a display.
Now you need about three gigabits per second of throughput for FullHD
resolution at 60 Hertz, even with USB 3.0 that's quite hard to do. So
DisplayLink employs motion detection and compression to at least make
it possible to watch a movie, which is very CPU-heavy.

Because the device also doesn't support any 3D acceleration, you have
to render all the frames using your built-in GPU and then send the
full frames via USB. I don't think that would be a lot of fun with our
phone hardware.


cheers,
Simon


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