Perhaps you could write an article (Article section here on amigans) describing why certain hardware isn't supported, why dma doesn't work, what can be done to get around it, alternative cards to use and so on. That is, describe the technical reasons, economical reasons etc.
That way we can point people to that article.
Of course I could do that, but what would it help? If you read Catalists posting, you see the typical rant. I don't think that any reasoning will reach him, more so since he apparently created this account just for the purpose of this rant.
The reasons are always the same, either no one actually was available for the driver, or the hardware doesn't support it. I don't think that people like Catalist could be reasoned with anyway.
Seriously, if you do want to contact me write me a mail. You're more likely to get a reply then.
And those claiming this are who? Really I don't think that an article would help. Face it, those people will clame things like this no matter what. They could show AOS 4 runing with DMA working and they would still write those thing for whatever reason they have to write it.
So I think that they better continue their work and ignore comments like that.
So - please Remove Troll user that have ZERO interesst on OS4 and bring no civilized discussion to an Amiga forum.
We don't suspend users just because they have a different opinion. Hit the report button and keep the troll pointing out of the public forums next time. Thanks.
I've seen some people starting to claim that dma doesn't work and implying that it's because of os4 since it doesn't work on the A1's either.
DMA does work on the A1, otherwise there would be no DMA-capable IDE devices, or 100/1000 MB network drivers.
Personally, I don't think that these claims will stop with anything I write, but just in case, here's a cut-and-paste quote for everyone:
-- CUT HERE -- DMA PCI cards on the classic do not work because neither the Mediators nor the Prometheus support DMA. Some of them can do DMA between cards on the PCI bus, but that requires
a) special drivers that are specifically adapted to this "feature" b) A bounce buffer in a PCI card, like a graphics card, so this does not work with e.g. AGA. c) Adoptions in the graphics driver so that it reports less memory than it actually has.
Overall, this "solution" was rejected for the wide-ranging consequences it has. You may claim that the Articia fix was done on the A1 as well, but these kinds of fixes are local to the driver and do not require any changes in the DMA-driver AND the graphics card driver.
Needless to say, the graphics memory DMA hack only works on PCI graphics cards, i.e. if you have a CyberVisionPPC, or a BlizzardVisionPPC, a Picasso IV, AGA, or any other Zorro 2/3 graphics card, you would need to put in an extra (possibly unused) graphics card just to be able to use this "solution". -- CUT HERE --
I hope this clears it up.
Seriously, if you do want to contact me write me a mail. You're more likely to get a reply then.
Ok thanks for the reply i'd like to make only two questions
1) is possible to use the old elbox driver to use the pci board like soundblaster and ethernet pci card ? If yes we have to use also the old graphic driver for voodoo ( mediator ) with the old soundblaster and ethernet driver or we can use the new graphic driver for the os4 with the old ?
2) As you said before, is possible to adapt the old driver to work on os4 or is a "big and trouble" work ?
1) is possible to use the old elbox driver to use the pci board like soundblaster and ethernet pci card ? If yes we have to use also the old graphic driver for voodoo ( mediator ) with the old soundblaster and ethernet driver or we can use the new graphic driver for the os4 with the old ?
Yes, this should be possible. It used to work, I haven't tried it in a while, and there is one potential pitfall. You would need to use either all AmigaOS 4.0-drivers or all-Elbox drivers.
The reaons for this are two-fold: One, you will need the Elbox graphics card driver since otherwise you do not get the additional memory buffer that is used as a bounce buffer for the DMA devices.
Two, the Elbox pci.library wants to retain the exclusive access to the Mediator hardware and more specifically, to the Mediator Offset Register. That means that the V52 expansion.library and pci.library might interfere with each other if both are trying to service "their" drivers. The result would invariably be trash.
The latter might also be an issue when you are using only Elbox drivers, but the code in expansion.library usually is dormant unless there is really something accessing PCI via the expansion.library.
Quote:
2) As you said before, is possible to adapt the old driver to work on os4 or is a "big and trouble" work ?
Not so much. In theory, you could even use a new feature of AmigaOS 4.0's rtg.library (pinned bitmaps) to create the bounce buffer without the need for a modified driver, but that would require that you know you are allocating a bitmap on the Voodoo 3, and that this Voodoo 3 is stuck into a Mediator. This is a bit shaky, but once you are use it would probably be relatively easy to adapt the drivers.
However, as I pointed out before, this requires a PCI Graphics card in the Mediator, it will not work with a Zorro card, or a BVisionPPC/CVisionPPC, or an AGA-only system.
Seriously, if you do want to contact me write me a mail. You're more likely to get a reply then.
There is a big difference in speed to use the native graphic library of amiga os 4.0 instead of Elbox library ?
Thanks
I suppose you will notice the difference, but I don't have any benchmarks that would illustrate it. I don't think that it will make a major difference, really.
Seriously, if you do want to contact me write me a mail. You're more likely to get a reply then.
Absolutely. Nice that my CSPPC which I bought when it was new (and very expensive) is finally going to be able to be used properly.
Of course ironically I have an A1 now so it's less useful than it would have been 10 years ago, but I'm just grateful it's out now! Can't do everything on an A1 after all (anything which uses OCS/ECS/AGA screenmodes for starters!).
It's a shame there's no DMA - that means no TV card drivers either, of course - but that's just the problem with these PCI adaptors on the Amiga, it seems. Can't everything, we should be thankful for what we've got, even if it's not perfect.
I really don't think much, if any, time has been spent over the last 4 years, developing to support the Classic Amiga A1200, maybe not even the A4000.
As if you had a frigging clue...
Neither Mediator nor Prometheus are capable of DMA (as in direct *MEMORY* access). Period. Mediator can busmaster between PCI cards, but that's it.
*IF* we were to support this kludge, we would need to change each and every driver that we have to support it. This is not realistic.
Bottom line, either the PCI busboards support DMA into the Amiga's main memory directly, or not. They don't. Hence, no DMA capabilities. Simple as that.