On Tue, May 02, 2006 at 02:30:43PM -0700, Greg KH wrote:
> On Tue, May 02, 2006 at 04:48:42AM -0400, Kyle Moffett wrote:
> > On May 2, 2006, at 00:00:53, Greg KH wrote:
> > >On Mon, May 01, 2006 at 07:29:23PM -0400, Kyle Moffett wrote:
> > >>So my question stands: What is the _recommended_ way to handle
> > >>simple data types in low-bandwidth/frequency multiple-valued
> > >>transactions to hardware? Examples include reading/modifying
> > >>framebuffer settings (currently done through IOCTLS), s390 current
> > >>state (up for discussion), etc. In these cases there needs to be
> > >>an atomic snapshot or write of multiple values at the same time.
> > >>Given the situation it would be _nice_ to use sysfs so the admin
> > >>can do it by hand; makes things shell scriptable and reduces the
> > >>number of binary compatibility issues.
> > >
> > >I really don't know of a way to use sysfs for this currently, and
> > >hence, am not complaining too much about the different /proc files
> > >that have this kind of information in it at the moment.
> > >
> > >If you or someone else wants to come up with some kind of solution
> > >for it, I'm sure that many people would be very happy to see it.
> >
> > Hmm, ok; I'll see what I can come up with. Would anybody object to
> > this kind of API (as in my previous email) that uses an open fd as a
> > transaction "handle"?
>
> No, I think Kay played around with something like using the open fd of
> the directory as such a lock (or was he using flock on it, I can't
> remember now...)
If you can assume that processes accessing the values are cooperative,
it already works without any changes:
$ time flock /sys/class/firmware echo 1 > /sys/class/firmware/timeout
real 0m0.005s
$ flock /sys/class/firmware sleep 5&
[1] 6468
$ time flock /sys/class/firmware echo 1 > /sys/class/firmware/timeout
real 0m3.558s
Kay
-
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]
