On Mon, Mar 17, 2014 at 10:34:25PM +0000, James Hogan wrote: >It's ambiguous the other way too (which is probably a strong point against >having actual protocol bits for each NEC variant, since they only differ in >how the scancode is constructed). E.g. the Tivo keymap is 32-bit NEC, but has >extended NEC scancodes where the bytes of the command are complements (i.e. >the extended NEC command checksum passes). This makes it hard to filter on at >the scancode level (the drivers will probably get it right for the hardware >filters, but the software filter will likely get it wrong in those corner >cases since it knows nothing of NEC). > >There's multiple ways the NEC scancode formats could be improved >(incompatibly!) to reduce the problems, but none are perfect. > >E.g. one possibility is to scrap the NEC and extended NEC scancodes and just >use 32-bit NEC scancodes format throughout: YES! All the "knowledge" of "original" NEC (16 bit), "extended" NEC, etc that have multiplied over both drivers and in various parts of rc-core is a big mistake IMHO. The only sane way of handling NEC is to always treat it as a 32 bit scancode (and only in cases where e.g. the hardware returns or expects a 16 bit value should the scancode be converted to/from the canonical 32 bit format). There is absolutely no advantages in trying to parse or "understand" the NEC format unless it absolutely cannot be avoided. I haven't had the time to really review your patches in depth, but whatever you do, please try to keep any knowledge of NEC 16/24/32 bit distinction out of any functionality you add. I had a suggested patch before which would also make the keymap handling 32-bit centric...essentially by redefining the set/get keymap ioctls a bit (with backwards compatibility that guesses if the scancode is 16/24/32 bit based). It's been on my todo list for a long time to dust it off...(yeah...I know)... >0x[16-bit-address][16-bit-command] > >which encodes scancodes for extended NEC like this: >0x[16-bit-address][~8-bit-command][8-bit-command] > >and normal NEC like this: >0x[~8-bit-address][8-bit-address][~8-bit-command][8-bit-command] > >Thanks >James -- David Härdeman -- 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
