Hi, just a short confirmation for cx88xx cards with external audio decoders. Am Samstag, den 21.02.2009, 09:56 -0300 schrieb Mauro Carvalho Chehab: > On Sat, 21 Feb 2009 13:45:40 +0100 > Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > > > tda9840 support is provided by tda9840.ko, but there's no > > > request_module() or any other reference (except for the above comment) to > > > it at bttv driver. I believe that this is not an isolated case. > > > > The tda9840 is handled by tvaudio. Other than tda9875 and msp3400 all these > > audio variants are all handled by that module. tvaudio was developed at the > > time as a sort of 'catch-all' module and is currently only used by bttv. > > > > If you look at the code you'll se that tda9840.c can only be used with > > saa7146, ditto tea6420.c. So these give no conflicts. > > Ok. > > > > I suspect that there are other cases where no doc is provided on kernel > > > and the only source of information is provided by googling at the net or > > > by taking a look on each card at bttv-gallery to see what chips are > > > inside of each bttv board. > > > > > > So, at least for bttv, IMO, we should: do an i2c scan, on bttv driver, > > > for tvaudio and the other audio modules. If found, then we load the > > > proper driver. > > > > > > We'll still have another problem: There are conflicting addresses. For > > > example, address 0xb0 (8bit notation) is used on tvaudio for tda9874 and > > > on tda9875. I have no idea what boards need tvaudio and what boards need > > > tda9875 module. So, simply probing for 0xb0 won't be enough. > > > > Luckily the two chips can be told apart from one another. Suggestion: move > > the support for tda9874 from tvaudio.c to tda9875.c and let that one handle > > both. They are very similar and that shouldn't be difficult. That will > > solve this conflict in an elegant manner. > > > > I see one more conflict between msp3400 and tea6300. It should be possible > > to implement i2c detect support in msp3400 since that chip can detect what > > chip it is, and if no msp3400 is found after all we fall back to tvaudio. > > Seems the better solution for me also. > > > > During the conversion of bttv to V4L2, I've mapped the i2c addresses of > > > the audio modules I found at: > > > > > > linux/include/media/i2c-addr.h > > > > > > For cx88, the issue is simpler, since cx88 has its own audio decoder. I > > > dunno why some PV boards have a separate audio processor[1]. Anyway, for > > > cx88, we can add the autodetection code just for that device, and just > > > for tvaudio. > > > > Are you sure cx88 requires that tvaudio is loaded for some cards? There is > > no mention about tvaudio and cx88 anywhere, neither source nor > > documentation, nor google for that matter. > > Yes, I'm sure. It were reported by one user at #v4l irc channel. I think some > emails were exchanged also (not sure if they were in priv or not). On that > time, I asked him to submit a patch creating a separate entry for that PV > variant, but he didn't. After some time, we lost contact with him. Such cards do exist. Here is one thread. http://threebit.net/mail-archive/video4linux/msg01432.html He forgot to attach his patch and finally used the existing card entry with tvaudio. This user was from Portugal, but later those cards were also reported from Poland. They came with CX 23880-16 !! and LG TPI8PSB02, TUNER_LG_PAL_FM (28) with the special radio mode switch 0xa5. BTW, it is also an explicit design option for saa7134 and saa7133 chips to use external audio decoders for standards not supported internally, but I think not used so far. > > > This will be great, provided that we can do the autoprobing for the audio > > > modules as required by a few drivers like bttv. > > > > You cannot expect that a user can modprobe an i2c driver and it will > > magically appear. That's going away. You can change the driver so that it > > will load the module and let it probe for a series of i2c addresses. There > > is also an option to let the i2c driver do additional checks (Jean knows > > more about the details). > > We need one solution. For sure it is better if the i2c adapter to do such probing. > Cheers, Hermann -- 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
