On 12/21/05, Neil Brown <[email protected]> wrote:
> On Wednesday December 21, [email protected] wrote:
> > On 12/21/05, Neil Brown <[email protected]> wrote:
> > >
> > > I suggested an early of this patch some time ago to see if it was an
> > > acceptable approach and got zero feedback, which presumably means it
> > > is perfect:-)
> > >
> > > I've now reviewed it, fixed up the bits I didn't like, and tested it.
> > > It works and I am happy with in.
> > >
> > > So: I would like to submit it for inclusion in a future kernel.
> > >
> > > Comments, or acks, please :-)
> > >
> > [snip]
> > > +/* Sysfs attribute files are pollable. The idea is that you read
> > > + * the content and then you use 'poll' or 'select' to wait for
> > > + * the content to change. When the content changes (assuming the
> > > + * manager for the kobject supports notification), poll will
> > > + * return POLLERR|POLLPRI, and select will return the fd whether
> > > + * it is waiting for read, write, or exceptions.
> > > + * Once poll/select indicates that the value has changed, you
> > > + * need to close and re-open the file, as simply seeking and reading
> > > + * again will not get new data, or reset the state of 'poll'.
> >
> > What if the value changes again between me closing and re-opening the file?
>
> You miss an intermediate event I guess.
>
> If you have a stream of events where you absolutely want to see every
> one of them, then you want something like a character-device (or one
> of several other alternative).
> That is not what this is for.
>
> However very often you don't need to see every single event. You just
> need to know when state has changed so you can respond to the new
> state.
> That is what this patch is for.
>
> Does that answer your question?
>
Yes it does. Thanks.
--
Jesper Juhl <[email protected]>
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please http://www.expita.com/nomime.html
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
