On Wed, 23 May 2007, Alan Stern wrote:

> > > I suspect it is keyboard-dependent.  For example, the keyboard's 
> > > internal buffer might be able to hold no more than one event, 
> > > because the designers expected the host to poll frequently.  Since 
> > > the polling can't occur during the wakeup interval, multiple events 
> > > from that time will get lost.
> > in such situation, I'd however expect the first N events to be lost, 
> > but the last events to arrive without problem. What I am experiencing, 
> > however, is that the missing events are usually "the middle" ones.
> It depends on how the buffer is implemented.  It might work this way:  
> The first keystroke is detected, goes into the buffer, and causes a 
> remote wakeup request to be sent.  Later keystrokes can't go into the 
> buffer because the buffer is still full, so they are dropped.  When the 
> resume sequence is complete, the host reads the original keystroke and 
> the buffer is once again empty.  Hence any further keystrokes are 
> processed as usual.

Hi Alan,

you are right, however there is still a reason I think that this is not 
the case. 

What I am seeing is that the keypresses are lost only if I hit a key (and 
thus wake the autosuspended keyboard up) only after a short time it goes 
to suspend. When I leave it autosuspended for 2 or more seconds 
(approximately), it behaves nicely.

Sure, it still could be a HW issue (I have experienced this with two 
random keyboards I used for testing), but I'd guess it would be something 
different than what you describe. What do you think?

Thanks,

-- 
Jiri Kosina
SUSE Labs

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