[PATCH xf86-input-synaptics] Drain XRecord connection of any events after handling replies

[Peter Hutterer]

On Fri, Apr 15, 2011 at 03:29:57PM -0400, Chase Douglas wrote:
> If the X server sends an event to the XRecord connection the event
> will never be handled. This will cause the event queue to fill up in
> Xlib and lead to syndaemon running away at 100% cpu usage.
> 
> This change drains any events from the connection. It's not a fix for
> the underlying bug in the server or Xlib, but it does paper over the
> issue for now.
> 
> https://bugs.launchpad.net/bugs/754470
> http://bugs.freedesktop.org/show_bug.cgi?id=31921
> 
> Signed-off-by: Chase Douglas <chase.douglas at canonical.com>
> ---
> I'm offering this up as a work around for whatever real bug exists. It
> probably should not be committed upstream though.
> 
>  tools/syndaemon.c |    8 ++++++++
>  1 files changed, 8 insertions(+), 0 deletions(-)
> 
> diff --git a/tools/syndaemon.c b/tools/syndaemon.c
> index 0309fb5..1c799c6 100644
> --- a/tools/syndaemon.c
> +++ b/tools/syndaemon.c
> @@ -415,6 +415,14 @@ void record_main_loop(Display* display, double idle_time) {
>  
>  	    XRecordProcessReplies(dpy_data);
>  
> +	    /* If there are any events left over, they are in error. Drain them
> +	     * from the connection queue so we don't get stuck. */
> +	    while (XEventsQueued(dpy_data, QueuedAlready) > 0) {
> +	        XEvent event;
> +	        XNextEvent(dpy_data, &event);
> +	        fprintf(stderr, "bad event received, major opcode %d\n", event.type);
> +	    }
> +
>  	    if (!ignore_modifier_keys && cbres.key_event) {
>  		disable_event = 1;
>  	    }
> -- 
> 1.7.4.1
 
fair call, though I'd appreciate it if you could figure out why the events
are sent on the record connection (and if that is indeed a bug or just
unhandled behaviour on the syndaemon side).

pushed, thank you.

Cheers,
  Peter