Re: Is it useful to support user level drivers

David S. Miller
2001-06-22T00:36:31Z

Mike Mackovitch writes:
> On Thu, Jun 21, 2001 at 04:22:32PM -0700, David S. Miller wrote:
> > What the heck is ULI then? I've actually read the assembly code for
> > this back when I did my SGI internship.
>
> If my memory serves me correctly, I believe ULI was some
> hacked up "user-level interrupt" feature. I have no idea
> who (if anyone) used it, but it definitely wasn't used by
> SGI's graphics drivers.

Strange, because taking veritcal retrace interrupts directly in
userspace was the first thing that came to my mind when I saw
what ULI was doing.

When IRIX optimizes something to the extreme, it is either for
big-iron or graphics performance, very few exceptions exist :-)

Later,
David S. Miller
davem@redhat.com