On Mon, Aug 16, 2010 at 4:41 PM, Maxim Levitsky <maximlevitsky@xxxxxxxxx> wrote: > On Mon, 2010-08-16 at 00:04 -0400, Jarod Wilson wrote: >> 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. > > Just one minor nitpick. > You could 'use' the original RC5 decoder, but add a knob to it to make > it accept 15 bits instead of 14. > However, this will require some interface changes. Well, I think that still falls down if someone, for some reason, wants to use both an old RC5 remote and the Streamzap remote at the same time. I think a parallel decoder is probably the best situation for the moment, as both 14-bit RC5 and Streamzap RC5 can be decoded simultaneously. -- 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
