On Mon, 2009-12-07 at 13:19 -0500, Jarod Wilson wrote: > On Nov 26, 2009, at 2:43 PM, Andy Walls wrote: > > > On Thu, 2009-11-26 at 12:05 -0200, Mauro Carvalho Chehab wrote: > >> Krzysztof Halasa wrote: > >>> Andy Walls <awalls@xxxxxxxxx> writes: > >>> > >>>> I would also note that RC-6 Mode 6A, used by most MCE remotes, was > >>>> developed by Philips, but Microsoft has some sort of licensing interest > >>>> in it and it is almost surely encumbered somwhow: > >>> > >>> I don't know about legal problems in some countries but from the > >>> technical POV handling the protocol in the kernel is more efficient > >>> or (/and) simpler. > >> > >> A software licensing from Microsoft won't apply to Linux kernel, so I'm > >> assuming that you're referring to some patent that they could be filled > >> about RC6 mode 6A. > >> > >> I don't know if is there any US patent pending about it (AFAIK, only US > >> accepts software patents), but there are some prior-art for IR key > >> decoding. So, I don't see what "innovation" RC6 would be adding. > >> If it is some new way to transmit waves, the patent issues > >> aren't related to software, and the device manufacturer had already handled > >> it when they made their devices. > >> > >> If it is just a new keytable, this issue > >> could be easily solved by loading the keytable via userspace. > >> > >> Also, assuming that you can use the driver only with a hardware that comes > >> with a licensed software, the user has already the license for using it. > >> > >> Do you have any details on what patents they are claiming? > > > > The US Philips RC-6 patent is US Patent 5,877,702 > > > > http://www.google.com/patents?vid=USPAT5877702 > > > > Click on download PDF to get a copy of the whole patent. > > > > I am not a lawyer. Philips claims' all appear to tie to a transmitter > > or receiver as part of a system, but most of the claims are about > > information and bit positions and lengths. > ... > > IMO, given > > > > a. the dearth of public information about RC-6, indicating someone > > thinks it's their trade secret or intellectual property > > > > b. Microsoft claiming to license something related to the MCE remote > > protocols (which are obviously RC-6 Mode 6A), > > > > c. my inability to draw a "clear, bright line" that RC-6 Mode 6A > > encoding and decoding, as needed by MCE remotes, implemented in software > > doesn't violate anyone's government granted rights to exclusivity. > > > > I think it's much better to implement software RC-6 Mode 6A encoding and > > decoding in user space, doing only the minimum needed to get the > > hardware setup and going in the kernel. > > > > Encoding/decoding of RC-6 by microcontrollers with firmware doesn't > > worry me. > > > > > > Maybe I'm being too conservative here, but I have a personal interest in > > keeping Linux free and unencumbered even in the US which, I cannot deny, > > has a patent system that is screwed up. > > So I had one of the people who does all the license and patent audits > for Fedora packages look at the Philips patent on RC-6. He's 100% > positive that the patent *only* covers hardware, there should be no > problem whatsoever writing a software decoder for RC-6. OK. Thanks for having some professionals take a look. (I'm assuming that's the only patent.) So I'll whip up an RC-6 Mode 6A decoder for cx23885-input.c before the end of the month. I can setup the CX2388[58] hardware to look for both RC-5 and RC-6 with a common set of parameters, so I may be able to set up the decoders to handle decoding from two different remote types at once. The HVR boards can ship with either type of remote AFAIK. I wonder if I can flip the keytables on the fly or if I have to create two different input devices? Regards, Andy -- 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
