Re: [PATCH 3/4] input: evdev: Indicate buffer overrun with SYN_DROPPED.

Hi Henrik,

On Fri, Mar 25, 2011 at 2:02 AM, Henrik Rydberg [off-list ref] wrote:

My last comment was not right, the SYN_DROPPED is pushed ahead in the
buffer, sorry about that. However, this change does not shrink the
number of buffered elements in case of an overrun, which has been
discussed before as a possibly important feature of the current
code. I would be more comfortable prepending the head with a
SYN_DROPPED, like this:

if (client->head == client->tail) {
       struct input_event drop;

       drop.time = event->time;
       drop.type = EV_SYN;
       drop.code = SYN_DROPPED;
       drop.value = 0;
       client->buffer[client->head++] = drop;
       client->head &= client->bufsize - 1;

       client->buffer[client->head++] = *event;
       client->head &= client->bufsize - 1;
}

The main point is that if we end up having to drop an event, it is
likely we will have to drop the next one, too.

I think that's a good idea.  If the client is far behind then we might
as well truncate the buffer as you suggest.  I'll do that.

Jeff.
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