If you were Nvidia?

[UchihaMadara]

Hey Board

From what I understand Sony is really not in control of giving access to the GPU and extra RAM, It is Nvidia. Do any of your honestly think that Nvidia or Sony give us open source folk access to this last hold out on the PS3? Does giving free access to the GPU infringe on any financial or special interest of either company? Any ideas appreciated.

[ppietro]

Hey Board

From what I understand Sony is really not in control of giving access to the GPU and extra RAM, It is Nvidia. Do any of your honestly think that Nvidia or Sony give us open source folk access to this last hold out on the PS3? Does giving free access to the GPU infringe on any financial or special interest of either company? Any ideas appreciated.

Regarding the extra RAM.

That's not my understanding.

The issue is that there are two kinds of RAM in the PS3. 256 Megs of RAMBUS XDR main RAM and 256 Megs of GDDR3 video RAM.

The bridge chips in the PS3 can allow the RSX to use some of the main RAM as additional video RAM, but it doesn't appear as easy to go the other direction.

(Look at the chart on this page. Ignore the text in the article - it's incorrect. Main memory is the XDR, and Local Memory is the GDDR3. )

Especially not from a Linux perspective. It would be like trying to use the video memory on your video card as part of your system memory. No Linux to my knowledge currently lets you do this.

It's possible - but I think it would take a change to the kernel to make it happen.

The other possibility is that you could write a driver that would use the extra graphics memory as a RAMDISK, but I'm not sure how much that buys you either.

Some of this info is referenced here:
http://en.wikipedia.org/wiki/PlayStation_3_hardware#Central_processing_unit

here:
http://en.wikipedia.org/wiki/PlayStation_3_hardware#Graphics_processing_unit

and here:
http://en.wikipedia.org/wiki/RSX_%27Reality_Synthesizer%27

Cheers,
Paul

[uncholowapo]

Thats pretty bogus. How did Sony design a "supposedly next gen" console when its stats are down below the XBox 360. I mean Xbox is good and all but it came out before the ps3 and therefore should have given Sony a heck of enough time to rethink it's design. It could have taken advantage of the release. Also I think if nVidia did give open software programers access to the GPU and RAM it would give Linux way more options for programming and would not infringe on the financial status of either company, but that just my opinion.

[ppietro]

Thats pretty bogus. How did Sony design a "supposedly next gen" console when its stats are down below the XBox 360. I mean Xbox is good and all but it came out before the ps3 and therefore should have given Sony a heck of enough time to rethink it's design. It could have taken advantage of the release. Also I think if nVidia did give open software programers access to the GPU and RAM it would give Linux way more options for programming and would not infringe on the financial status of either company, but that just my opinion.

(friendly opinions and follow-up questions to follow. )

Sorry - I don't understand how you'd consider its stats are down below the Xbox 360. You mean for Linux or for playing games?

The PS3 has a much more non-traditional architecture than a 360. Normal PC architecture - like Linux expects - doesn't apply here.

What Linux considers the processor in the PS3 - the HyperThreaded PowerPC core - is only really used for setup and other overhead tasks. The Cell's other elements - the 6 SPEs - aren't general purpose processors that execute standard code - they're kinda like DSP math crunchers. In other words - the very abilities that make a PS3 a great game machine hobble it for Linux.

As one of the few owners of the PS2 Linux kit, I can tell you that running Linux on the PS2 was even stranger than running Linux on the PS3. PS2 Linux only had 32 Megs of RAM with a 200 MHz single threaded MIPS core. This is a fraction of the power of the PS2's Emotion Engine. It really wasn't designed to run programs like that - it's a pure game machine. PS3 Linux is pretty decent by comparison - not equal to a high end PC running Linux - but for a console - it's pretty great.

Only the PS1 had what you'd consider a "PC Like" architecture. Normal PlayStation programming is done by a moderately fast processor for setup and a number of high speed DSPs crunching data that is streamed back and forth thru high bandwidth DMA. (See a pretty detailed description of the setup here.) This is quite different from a PC/360-like fast central processor and video card. Heck - the PS2 doesn't even really have a video card: with a 2560 bit-wide bus (not a typo!) - the GS is more like a frame buffer compositor than a graphics card.

As far as giving access to the GPU and RAM - I think it would affect the financial status of both companies. That opens a huge can of worms - because at that point - you could copy decrypted PS3 games to the hard disc, and run them from Linux at full speed. I actually understand why this restriction is in place.

That being said - I do think there's room for improvement in the Linux graphics department. There's gotta be some kind of compromise that makes everyone happier - if not outright happy.

Cheers,
Paul

[uncholowapo]

You make a pretty good argument touche. So do you think linux on the ps3 could benifit from a little juice from the GPU RSX or would you still accept it like it is right now?

[ppietro]

You make a pretty good argument touche. So do you think linux on the ps3 could benifit from a little juice from the GPU RSX or would you still accept it like it is right now?

Oh - without question - being able to access the RSX directly would definitely benefit PS3 Linux.

Since the RSX is similar to an nVidia 7800 in a PC, Linux would actually know how to talk to that, as opposed to trying to work around the non-standard bits in the rest of the PS3 architecture.

Allowing access would be like taking the old videocard out of a PC, and dropping in a fast nVidia - without physically changing the hardware at all.

At least the hypervisor for PS3 presents Framebuffer/SDL support, which has some support in Linux. This was always an issue with PS2 Linux - since they only had the GS chip for graphics output, you had to get custom drivers from Sony, which had mixed success with Linux applications.

There may be some workarounds for this. Sony hasn't ruled out complete access to the RSX. They just need to figure out something acceptable to everyone involved - Linux hobbyist and Game Publisher alike. As an example - they could open up the RSX for 2D acceleration and provide pseudo-3D acceleration via OpenGL running on the SPEs. This would prevent game piracy, yet still allow Linux apps to take advantage of video and 3D acceleration.

This is all new territory - both for Linux and for the PS3. I'm keeping my fingers crossed that a good, workable solution will be found for this.

Cheers,
Paul