On Thu, Aug 12, 2010 at 2:46 AM, Christoph Bartelmus <lirc@xxxxxxxxxxxx> wrote: ... >> So I spent a while beating on things the past few nights for giggles >> (and for a sanity break from "vacation" with too many kids...). I >> ended up doing a rather large amount of somewhat invasive work to the >> streamzap driver itself, but the end result is functional in-kernel >> decoding, and lirc userspace decode continues to behave correctly. RFC >> patch here: >> >> http://wilsonet.com/jarod/ir-core/IR-streamzap-in-kernel-decode.patch >> >> Core changes to streamzap.c itself: >> >> - had to enable reporting of a long space at the conclusion of each >> signal (which is what the lirc driver would do w/timeout_enabled set), >> otherwise I kept having issues with key bounce and/or old data being >> buffered (i.e., press up, cursor moves up. push down, cursor moves up >> then down, press left, it moves down, then left, etc.). Still not >> quite sure what the real problem is there, the lirc userspace decoder >> has no problems with it either way. >> >> - removed streamzap's internal delay buffer, as the ir-core kfifo >> seems to provide the necessary signal buffering just fine by itself. >> Can't see any significant difference in decode performance either >> in-kernel or via lirc with it removed, anyway. (Christoph, can you >> perhaps expand a bit on why the delay buffer was originally needed/how >> to reproduce the problem it was intended to solve? Maybe I'm just not >> triggering it yet.) > > Should be fine. Current lircd with timeout support shouldn't have a > problem with that anymore. I was already thinking of suggesting to remove > the delay buffer. Cool, sounds like a plan then, I'll go ahead with it. >> Other fun stuff to note: >> >> - currently, loading up an rc5-sz decoder unconditionally, have >> considered only auto-loading it from the streamzap driver itself. Its >> a copy of the rc5 decoder with relatively minor tweaks to deal with >> the extra bit and resulting slightly different bit layout. Might >> actually be possible to merge back into the rc5 decoder itself, >> haven't really looked into that yet (should be entirely doable if >> there's an easy way to figure out early on if we need to grab 14 >> bits). > > There is no way until you see the 14th bit. Hm. Was afraid of that. I gave it a shot to see if I could make that work, pretty shaky results. About 2/3 of the keys get decoded as 15-bit streamzap, the other 1/3 get decoded as 14-bit RC5, and don't match anything in the keytable (and often duplicate one another). So it looks like at least for the time being, a separate parallel decoder is the way to go. I'm thinking that I like the approach of only explicitly loading it from the streamzap driver though. -- Jarod Wilson jarod@xxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
