On Wed, Nov 17, 2010 at 12:26:36AM +0100, David Härdeman wrote: > On Tue, Nov 16, 2010 at 10:08:29AM -0200, Mauro Carvalho Chehab wrote: ... > >Also, changing the current tables to 32 bits will break userspace API, as all > >userspace keytables for NEC will stop working, all due to a few vendors that > >decided to abuse on the NEC protocol. This doesn't sound fair. > > The NEC protocol is hardly a standard. There's lot's of variations out > there. And intentionally throwing away information inside the kernel > doesn't sound fair either. > > >Considering that the new setkeycode/getkeycode ioctls support a variable > >size for scancodes, it seems to me that the proper solution is properly > >add support for variable-size scancode tables. By doing this, one of the > >properties for a scancode table is the size of the scancode. The NEC decoding > >logic can take the scancode size into account, when deciding to check checksum > >or not. > > With that approach you'd have to have the same scancode mangling code in > each driver which generates NEC scancodes as well as in the nec raw > decoder. > > One suggestion would be to use a full 32-bit scancode table, but use the > size from the ioctl to determine how to generate the scancode to be > inserted into the table. So if the ioctl was called with a 2 byte > scancode, assume NEC with addr(8 bits) + cmd(8 bits); 3 byte -> NEC > Extended with addr(16 bits) + cmd(8 bits); 4 byte -> 32 bit scancode. > > That way the nec decoder and other scancode drivers can be kept simple, > the scancode table has a full 32 bit scancode for all keys and userspace > won't see the difference (though I still think we should use the new > large scancode API to let userspace properly indicate the protocol along > with the scancode in the future). I hacked together a semi-nasty variant of this, which I already know Mauro isn't too keen on, but its perhaps a step in the right direction. At least, its hopefully better than a modparam approach... ;) http://git.kernel.org/?p=linux/kernel/git/jarod/linux-2.6-ir.git;a=commitdiff;h=a2eabcb44fa72e98a912c05a23659d0c946a17e5 http://git.kernel.org/?p=linux/kernel/git/jarod/linux-2.6-ir.git;a=commitdiff;h=164dc9cf5dec582bda5f7a059957ac2da2b0c1aa Mauro's suggestion, iirc, was that max scancode size should be a property of the keytable uploaded, and something set at load time (and probably exposed as a sysfs node, similar to protocols). However, the one issue I see there is that if someone loads a 16-bit keytable, then does a single scancode replacement with something much larger, how are we going to handle that? -- Jarod Wilson jarod@xxxxxxxxxx -- 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
