[MPlayer-dev-eng] DMA or not DMA
Arpi
arpi at mplayerhq.hu
Wed Jan 5 23:04:08 CET 2005
Hi,
any news on this? (implementing DMA support for mga_vid)
my sponsor is interested if we can do it soon (in 2-3 weeks)
or they have to find different solution...
if anybody interested implementing this, tell me.
also tell me (in public or private) how much money it costs...
so i can pass it to the sponsor.
> On Wed, 24 Nov 2004 15:37:17 -0300
> Daniel Serpell <daniel_serpell at yahoo.com> wrote:
>
>
> > > btw, is it possible at all to run multiple dma transfers (to
> > > different cards) in the same time? or bus-mastering is about it?
> > > (ie only one dma transfer over pci bus)
>
> You can set up multiple dma transferes w/o problem, as long as
> the dma controller has free channels. Of course, only one transfere
> at a time is possible unless you have multiple independent busses.
>
> I dunno how linux handles this, but i guess that linux keeps
> it's own buffer for pending dma transferes and processes one
> after each other (at least, that would be what i do)
>
> > There should be only one bus-master on the bus at any given time,
> > so there is bus-arbitration going on. Normally, each bus-master
> > transfer takes at least about 16 words (ie, 64 bytes in PCI-32)
> > and then the bus is released. The "latency-timers" on each PCI
> > card give the bus information about when a master should release
> > the bus.
>
> Latency is of no concern in this case as you want to show all
> frames at the same time. Additionaly it's actualy better to
> keep the transferese together to skip the setup phase
>
>
> Attila Kinali
>
> _______________________________________________
> MPlayer-dev-eng mailing list
> MPlayer-dev-eng at mplayerhq.hu
> http://mplayerhq.hu/mailman/listinfo/mplayer-dev-eng
>
>
A'rpi / MPlayer, Astral & ESP-team
--
Girls are like internet domain names, the ones I like are already taken.
More information about the MPlayer-dev-eng
mailing list