Thread: DMA to user space
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From: <And...@no...> - 2000-04-13 10:24:55
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Hi Andreas and Sebastien, I was wondering if you could give me some estimate of when to expect DMA transfer or mapping of iso data to user space? I would really want to have this for our DV decoder. Best regards, Anders Weitman PS. I'm still trying to get approval for releasing the code for the DV decoder but it's a difficult issue and the lawyers and patent people are a bit slow (: _____________________________________________________________________ Anders Weitman, M.Sc Phone : +46 (0)13 4611341 Development Engineer Fax : +46 (0)13 4611001 Nokia Home Communications Mobile : +46 (0)70 2141319 Diskettgatan 11 E-mail : and...@no... SE-583 35 Linkoping, Sweden Internet : www.nokia.com/multimedia/ |
From: Sebastien R. <Seb...@sy...> - 2000-04-14 00:45:43
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>>>>> "Anders" == Anders Weitman <And...@no...> writes: Anders> Hi Andreas and Sebastien, I was wondering if you could give me some Anders> estimate of when to expect DMA transfer or mapping of iso data to user Anders> space? I would really want to have this for our DV decoder. I am quite busy right now with my work, so I am not actively working on this at the moment. If you look at the list archive, a Japanese guy did write a patch for it, but it has to be modified to work with the current driver, and I think I will end up rewriting part of it anyway once I have some time. I will soon need it anyway, so I might work on this again in a month or two. In the mean time, we will need to define an API to get this working with the subsystem. -- Sebastien Rougeaux RSISE, The Australian National University |
From: Andreas B. <and...@mu...> - 2000-04-14 01:40:55
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On Thu, Apr 13, 2000 at 01:05:57PM +0300, And...@no... wrote: > Hi Andreas and Sebastien, > > I was wondering if you could give me some estimate of when to expect DMA > transfer or mapping of iso data to user space? I would really want to have > this for our DV decoder. Second on my ToDo list (after getting that subsystem initiated transactions and GUID collecting to work). The first step to zero copy would be to make the hardware drivers use subsystem provided buffers for iso receiving instead of their own (and write code to manage locking and automatic freeing of those buffers in the subsystem). After that exists it would be a small step to actually mapping those buffers to user space. I don't think implementing mapping in the current raw1394 would a good idea since it would have to be rewritten then. -- Andreas E. Bombe <and...@mu...> DSA key 0x04880A44 http://home.pages.de/~andreas.bombe/ http://linux1394.sourceforge.net/ |