Re: [PATCH v2] Input: evdev - Add EVIOC mechanism to extract the MT slot state

["Henrik Rydberg" <rydberg@euromail.se>]

On Fri, Jan 06, 2012 at 12:23:42PM -0800, Dmitry Torokhov wrote:
> On Fri, Jan 06, 2012 at 09:14:34PM +0100, Henrik Rydberg wrote:
> > On Fri, Jan 06, 2012 at 12:02:40PM -0800, Dmitry Torokhov wrote:
> > > On Fri, Jan 06, 2012 at 08:48:15PM +0100, Henrik Rydberg wrote:
> > > > > > Ok, maybe not to so easy after all, which probably answers my own
> > > > > > question. Looks like a EVIOCGMTSLOT, taking both slot and event code
> > > > > > as argument, would be the cleaner route to take. Another ioctl, how do we
> > > > > > feel about that?
> > > > > 
> > > > > What's the problem with userspace locking?
> > > > 
> > > > The idea was to get by without it.
> > > > 
> > > > Regarding ioctls, it does not seem realizable due to ioctl number
> > > > exhaustion.
> > > 
> > > I am prettu sure we cabn spare 1 ioctl number. We just need to pass slot
> > > number not as part of ioctl number but in data instead. Like
> > > EVIOCGKEYCODE works.
> > 
> > Right, thanks. Perhaps we could even pass it as result data -
> > returning all mt data in one go? With the purpose being to capture the
> > full MT state, it ought to be both simpler and faster.
> 
> Yes, if caller passes buffer size and buffer address we can return all
> data in one go. We just need to make _really sure_ we are using 32/64 bit
> safe interface.

Yep. Great, I think we are getting closer. Will look into it.

Thanks,
Henrik