On 4/11/06, Steven M. Bellovin <smb@cs.columbia.edu> wrote:

>
> In all Unix drivers I've ever looked at, read calls block in the driver i=
f
> there's no data available.  The interrupt routine would wake the sleeping
> process, which would then copy the data to userspace and return.

Doesn't the driver have the option of returning EAGAIN, especially if
the process doesn't want to sleep on a read ?

--
~Cherry