The same discussion again and again... [LWN.net]

The same discussion again and again...

Posted Nov 5, 2011 19:08 UTC (Sat) by drag (guest, #31333)
In reply to: The same discussion again and again... by slashdot
Parent article: Rawhide gets GNOME Shell for all display types

> Well, because 3D hardware

There is increasingly no longer any such thing as '2D hardware' or '3D hardware'. 2D hardware in modern devices is completely and entirely gone.

Anyways even 2D hardware that existed on older cards had zero development resources. They are just copy and pasted designs from the earliest days of the first 3D acceleration video cards.

The amount of work required to get good 2D acceleration is just about the same as having good 3D acceleration.

So no matter what API you choose you will always end up with the pretty much the same destination if it's 'accelerated'.

To simplify your question instead of trying to compare Cairo vs OpenGL you should of just asked:

"Why didn't Gnome developers decide to limit themselves to 2D acceleration hardware?"

The answer is going to be:

"Because there is no longer any such thing as 2D acceleration hardware."
(for the most part)

to post comments

The same discussion again and again...

Posted Nov 6, 2011 1:36 UTC (Sun) by slashdot (guest, #22014) [Link] (4 responses)

Well, of course there is no 2D hardware at the moment, and in fact I'm not even sure if there ever was any 2D-only hardware capable of fully accelerating Render/Cairo (I guess not).

BUT the thing is that you might not have a working 3D driver (maybe because the only stable one available is proprietary and you refuse to use it, or it doesn't work on your kernel), or might be in a limited virtual machine, or you might be printing the screen contents to PDF or to an HTML/SVG page, or perhaps you want to reserve the GPU for actual 3D games or 3D modelling software and not have the desktop hog it.

In those cases, a limited 2D API is much easier to make work efficiently and in a stable way then a generic 3D one.

For example, in software, Pixman is far more stable, much simpler, more portable and probably faster than LLVMPipe (at least if you use only a single thread).

And in the "print to PDF/PostScript/HTML/SVG" case, then you absolutely NEED a 2D API, since those formats just can't do 3D rendering (excluding WebGL and other very new innovations).

The same discussion again and again...

Posted Nov 7, 2011 1:27 UTC (Mon) by drag (guest, #31333) [Link] (3 responses)

Having OpenGL API support is a basic feature that has existed for _decades_ on any respectable desktop system.

Forcing yourself to use multiple backends of APIs that are poorly suited to what you want do seems incredibly counter productive.

Why should a developer abandon the use of perfectly good APIs just because some users choose to go out and buy hardware that requires closed source software to function, then refuses to run closed source software? It's that a bit weird?

What I find disturbing is that Linux users are still willing to go out and spend good money on hardware and put a great deal of time into setting up software that will invariably lead pathologically broken setup. Then they expect that everybody must work around the problems they inflicted on themselves.

[quote]In those cases, a limited 2D API is much easier to make work efficiently and in a stable way then a generic 3D one.
[/quote]

I think what we are trying to do is point out to you that: No, this is not a true statement at all. The work required to get decent 2D acceleration on modern hardware is not any different then what it takes to get 3D acceleration.

OpenGL is not DirectX. Hardware support is entirely optional. It's just that Mesa OpenGL software reference, sucked. Now it does not suck nearly as much.

[quote]And in the "print to PDF/PostScript/HTML/SVG" case,[/quote]

A) I don't know why this case matters at all. Can you point me to a single example of people rendering their entire desktop output to PDF?

B) The choice of Gnome-shell developer's API does not impact the decision of the application developer. They can use whatever APIs they please. If they want to use something that has the ability to render their output to SVG or PDF or whatever then the Window manager does not enter into it at all.

The same discussion again and again...

Posted Nov 7, 2011 16:33 UTC (Mon) by raven667 (subscriber, #5198) [Link]

[quote]And in the "print to PDF/PostScript/HTML/SVG" case,[/quote] A) I don't know why this case matters at all. Can you point me to a single example of people rendering their entire desktop output to PDF?

AFAIK MacOSX uses PDF as its display language but it is accelerated by the GPU hardware so PDF is not mutually exclusive with using the GPU. In fact I don't understand this segue at all, what possible reason would rendering a PDF or HTML document cause you to not be able to use hardware accelerated graphics.

The same discussion again and again...

Posted Nov 9, 2011 19:31 UTC (Wed) by wookey (guest, #5501) [Link] (1 responses)

Why should a developer abandon the use of perfectly good APIs just because some users choose to go out and buy hardware that requires closed source software to function, then refuses to run closed source software?

There isn't necessarily much choice about it:

This here desktop was provided by IT in a large corp. The built-in graphics is disabled and an nvidia card shoved in. I can't change that - it's locked-down by IT.

More seriously, on ARM there are 6 different GPUs available and _all_ of them require binary drivers. I can't buy _any_ hardware that has accelerated graphics without getting into the above sticky situation. We both agree it's a crappy situation to be in, but short of telling me I should choose an entirely different CPU architecture, I can't really be blamed for _choosing_ this situation.

You can change OS, but not the hardware?

Posted Nov 9, 2011 20:41 UTC (Wed) by khim (subscriber, #9252) [Link]

This here desktop was provided by IT in a large corp. The built-in graphics is disabled and an nvidia card shoved in. I can't change that - it's locked-down by IT.

And yet you can change the OS? Hard to believe. If everything is indeed nailed down then "user" here is not you, it's your IT department. You are merely a commuter. You have my condolences but I don't see why I should jump hoops to accommodate your needs.

We both agree it's a crappy situation to be in, but short of telling me I should choose an entirely different CPU architecture, I can't really be blamed for _choosing_ this situation.

Then we should all agree that today ARM is crappy architecture - not because of CPU (which is also not all that rosy: try to find a free documentation on ARM architecture, for example), but because of GPU - and side with the Intel in it's fight with ARM. Or use binary blob if you prefer that.

You can not pay money to people who push GPUs which require binary blobs and then expressly refuse to use said blobs: you are not helping anyone because producers of said GPU don't really care all that much what you do with them if you paid good money anyway. Either start cracking blob (if you live in a country which allows such activity) or use it "as is" or stop buying this stuff. In this case you don't even have my condolences.

As I've noted before: if you've bought piece of hardware which requires binary blob - you've accepted it. Period. End of story. Live with the consequences. If you throw away said blob after the sale you'll just make your life more miserable - it does not affect the manufacturer at all.

P.S. Of course there are possibility that you've bought ARM chip for some highly specialized project and you don't actually need a GPU at all... but then the question arises: what this have to do with GNOME? GNOME is desktop environment intended for desktops, laptops - how is it relevant to your highly specialized ARM endeavour?