trinity-devel@lists.pearsoncomputing.net

Message: previous - next
Month: March 2012

Re: Re: [trinity-devel] ARM and Trinity and Raspberry Pi

From: Martin Gräßlin <mgraesslin@...>
Date: Sat, 03 Mar 2012 14:47:35 +0100
On Saturday 03 March 2012 02:36:00 Tiago Marques wrote:
> Raspberry Pi is the kind of device that can work reasonably with Trinity
> but not KDE4. Last time I checked I had Trinity running in 80MB for RAM
> while KDE4 was having trouble fitting in 600MB. For people who asked about
> reasons to keep KDE3 alive in Trinity, I would point to a working testbed,
> if we ever get to assemble one.
Hi Trinity developers,

it is great that you start to find reasons for Trinity. This is really needed 
and can only improve your product.

But please stop comparing to KDE. I have pointed it out before and I say it 
again: for a successful Trinity you may not be in competition with KDE. 
Finding arguments for the existance of Trinity based on "shortcomings" of KDE 
is not the right way. It only makes KDE developers not wanting to have 
anything to do with you. And also there is (like in this case) a high risk 
that you embarrass yourself.

Now I placed "shortcomings" in quotes. Why? Well because you are pretty bad 
informed about the state of KDE and ARM based devices like the Raspberry Pi. 
Have a look at  for example [1].

What you have to understand is that lightweight hardware and old hardware are 
two different type of kinds. While it is reasonable that Trinity works better 
on old hardware than KDE the same is not even closely true for lightweight 
hardware.

Let's have a look at the application I maintain (KWin) which exists both in 
Trinity and in KDE 4. Trinity's answer to compositing is either no compositing 
or XRender based compositing. Now hardware like the Raspberry Pi is not meant 
for no compositing or XRender. The driver just does not accelerate the 
rendering there. So if you use XRender or no compositing everything is 
rendered on the CPU. That's quite bad. What the GPU does really good is OpenGL 
ES based rendering. That's what KWin 4 uses on such hardware. KWin 4 is 
optimized to run well on lightweight modern hardware, but is not optimized for 
old hardware which does not provide OpenGL (ES). So this is a nice example to 
understand that old != lightweight.

May I ask how much experience the Trinity project has on working well on ARM? 
My guess is pretty much none. Do you expect any of your software to be 
optimized for ARM? Do you have any software running on ARM? Do you think Qt 3 
works as well as Qt 4 on ARM?

Well let's check the facts. Trolltech has been bought by a major mobile 
devices company which uses ARM CPUs in all of their products after Qt 4 has 
been released (also after KDE 4 has been released). Since then Qt has been 
optimized for the usage on ARM. I have here a Maemo (N900), a MeeGo (N950) and 
a Symbian 3 (C7) based device which uses Qt as the primary toolkit. Do you 
really think Qt 3 is anywhere up to what Qt 4 provides?

Now what about KDE? Did you know that the N9 ships KDE based software on the 
default installation? Did you know that there are quite some applications 
available in the OVI store (e.g. Marble) and some applications have been 
packaged (like Kontact touch)? Did you know that many developers have had ARM 
based devices like the PandaBoard for quite some time? Did you know that there 
are distributions actually testing that everything of KDE at least compiles on 
ARM? Did you know that you can very soon buy an ARM based tablet with KDE 
Plasma Active preinstalled? It comes also only with 512 MB of RAM, so no big 
difference to the Raspberry Pi.

I have taken the time to write this mail not to upset you, but to show you how 
dangerous such statements may be.

Kind Regards
Martin Gr��lin

[1] http://twitpic.com/7dfw5p

Attachments: