[BRLTTY] missing key release events, was Re: brltty5.2 alpine2.11 cursor tracking

[Nicolas Pitre]

On Wed, 7 Oct 2015, Dave Mielke wrote:

> [quoted lines by Nicolas Pitre on 2015/10/06 at 19:42 -0400]
> 
> >With those few patches I sent you separately to improve PCM code 
> >efficiency, the above test case is now more difficult to trigger.  So 
> >those patches don't completely fix it but they apparently help.
> 
> Please give the tune-thread branch a try. It needs more work, but it should 
> work well enough to test the problem.

Yes, problem entirely gone while using that branch.  Good work! And that 
is with the original PCM generator code in place.  I also forced every 
note to be 500ms long to exacerbate the issue to be sure.  With this 
hack it was easy to bring brltty in a loop where the bounce tune took 
all the CPU's attention which prevented it from seeing the release key 
event and therefore auto-repeat kicked in which generated yet more 
bounce tunes.  With the threaded tune this doesn't happen anymore. 
Another nicety: the braille cursor does not stop blinking while a tune 
is playing.

BTW, I instrumented the code to see the effect of those PCM efficiency 
patches I sent you.  Generating 100000000 samples and discarding them 
from within writePcmData() takes 14 seconds on my PC.  Doing the same 
with my 2 patches applied brings that down to 9 seconds. I suspect the 
relative difference would be even bigger on portable devices.


Nicolas