Re: Calculating kernel logical address ..

David S. Miller
2002-09-09T18:20:30Z

From: "Richard B. Johnson" <root@chaos.analogic.com>
Date: Mon, 9 Sep 2002 14:00:35 -0400 (EDT)

Well I just read Documentation/DMA-mapping.txt as advised by David
and it seems as though it will no longer be possible to do what
many programmers have been wanting to do, to wit:

(1) In user-code, allocate a buffer.
(2) Lock that buffer into memory.
(3) Call some driver that DMAs data to/from that buffer.

Video capture drivers and ALSA layer in 2.5.x kernel do
this perfectly fine. Perhaps you should have a look
at how they handle DMA on PCI.