Re: changing buffer size in kernel space

On Thu, Jun 06, 2002 at 02:57:42AM -0400, Chris Angell wrote:
> A couple months ago in a post, it was mentioned that you can't change
> the buffer size in kernel space.  Why is that exactly?  Is it a
> constraint on the device or the driver?

It's a kernel limitation.  The code that the driver calls needs to
do a lot of work to reallocate a buffer, including making enough
pages available, locking them, and getting the physical and bus
addressed for each.  It needs to be done in the context of a process,
so that it can sleep when necessary.

The preferred method for changing buffer size is comedi_config.  The
comedilib functions are provided because it's dumb not to.



dave...

Received on 2002-06-06Z18:59:10