Re: Direct access to IDE disk from kernel modules

Alan Cox (alan@lxorguk.ukuu.org.uk)
Mon, 15 Apr 2002 10:44:08 +0100 (BST)


> Is there a way to directly dump a buffer on an IDE disk from inside a
> kernel module without goig trough user space?
> I have written a driver for a frame grabber and would like be able to
> dump the frames real time directly to a dedicated IDE disk.
> My frames are already in a DMAble buffer.

You can get the same effect going via user space just fine, and the
performance of IDE is well below the point that should make a difference
since PCI bandwidth is likely to be your bottleneck.

mmap the capture buffers into a user application (eg video4linux api), then
write the files using the O_DIRECT option or a raw device (see rawctl and
friends)
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