Messages in this thread | | | From | "Christophe Beaumont" <> | Subject | RE: DMA memory limitation? | Date | Thu, 5 Jul 2001 10:07:17 -0700 |
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> On Thu, 5 Jul 2001, Vasu Varma P V wrote: > > > Hi, > > > > Is there any limitation on DMA memory we can allocate using > > kmalloc(size, GFP_DMA)? I am not able to acquire more than > > 14MB of the mem using this on my PCI SMP box with 256MB ram. > > I think there is restriction on ISA boards of 16MB. > > Can we increase it ? > > > > thx, > > Vasu > > 14MB of DMA(able) memory? Err. I think you are trying to > do something you would never need to do. > And what is that supposed to be????
I have a piece of pretty well designed hardware here... and my application requires me to have the PCI board to random access in master mode a whole lot of memory (anywhere from 128MEGS to 1GIG... and possibly more...) so I really do need BIG DMA buffers (I don't say huge anymore as one can get 1/2 Gig of RAM for just over 120 bucks???)...
There is no way I can have the piece of hardware behave in another fashion... and NO it is NOT broken (when you do BOTH hardware & software, you know about BOTH limitations... there are just some cases where you have to face some unique issues). the mem=1024M works pretty fine once you have figured out how to handle in a fairly simple way this "reserved" memory...
So please software people... do not blame it all on the hardware... =)
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