[GitHub] [incubator-nuttx] pkarashchenko edited a comment on pull request #5874: input/button: Remove the mulitple poll support

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pkarashchenko edited a comment on pull request #5874:
URL: https://github.com/apache/incubator-nuttx/pull/5874#issuecomment-1080382957


   >>  I have a general question. NPOLLWAITERS seems to be a more generic approach all over the code and buttons seems to be a partial case. Maybe it is more reasonable to set INPUT_BUTTONS_NPOLLWAITERS default value to 1 instead of removing it completely?
   
   > The problem is that the notification is unreliable. Since we just have one bo_pending per file handle and btn_read will clear bo_pending, the second poller may lose the event.
   
   >> Or you are going to iterate the code and apply similar change to other files?
   
   > touch and keyboard just support one poller per file handler, I will provide patch for ajoystack and djoystack.
   
   I understand the issue that you are describing, but I think that is how the concurrent access works. I mean if we take `CONFIG_NET_TCP_NPOLLWAITERS` case. We have only one `readahead` per connection (like `bo_pending` per file)
    and `tcp_readahead` potentially will clear the `readahead`, so the second poller may lose the event. Does this mean that we need to remove `CONFIG_NET_TCP_NPOLLWAITERS` as well? Please correct me if my example is wrong.


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