Messages in this thread | | | Date | Tue, 14 Aug 2012 14:06:45 -0700 | Subject | Re: [PATCH 02/19] Input: Improve the events-per-packet estimate | From | Ping Cheng <> |
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On Tue, Aug 14, 2012 at 1:01 PM, Henrik Rydberg <rydberg@euromail.se> wrote: > Hi Ping, > > Long time no see. :-) > >> > + /* Make room for KEY and MSC events */ >> > + events += 7; >> >> It is nice to get rid of the redundant pieces and to incorporate >> common functions. Thank you. >> >> I have a question about the code above though. Why do we use 7 >> instead of going through the keys like: >> >> for (i = 0; i < KEY_MAX; i++) >> if (test_bit(i, dev->keybit)) >> events++; > > Keyboards register a large amount of different keys, but seldom send > more than one or two at a time. The value 7 is ad hoc, admittedly, but > it makes the default buffer 8 bytes, which happens to precisely match > the default buffer in evdev.
That can be a valid reason until we need to report more keys simultaneously. Please update the comments so we know why we end up with 7.
Thank you.
Ping
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