Re: Re: [RFC/PATCHES] xc3028 hybrid tuner, em28xx/em2880-dvb, saa7134, cx88

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Hi Michael and others,

I know we've been over this, but I need to state my feelings on the matter, otherwise I would have to simply keep quiet, and that doesn't help the situation for anybody. I _strongly_ feel that the core changes being proposed here will hurt the integrity of the dvb subsystem.

I don't think they will hurt the integrity of the subsystem, but a large amount of changes can really affect the driver stability, even being trivial changes. Such patch series, if applied, will need acks for the active driver maintainers that should make sure this won't break any other driver.

I would, instead, use a different approach, without losing the required functionalities for xc3028.

To give my $2 cents of contribution, I've sent a modified version of dvb integration for xc3028 sometime ago to Markus, as a sugestion.

It should be noticed that I didn't tested the patchset (as currently I don't have em288x+xc3028 DVB hardware). If someone wants to take a look, the patch series it is available (at quilt format) at:
	http://linuxtv.org/~mchehab/mrec2/

The required changes on DVB are minimal (just adding a few newer fields at frontend core). Also, there's no need to change any stuff on dvb or v4l drivers. So, it wouln't break any existing drivers.

The diffstat for the core changes is:

 linux/drivers/media/Kconfig                     |    2
 linux/drivers/media/Makefile                    |    1
 linux/drivers/media/dvb/dvb-core/dvb_frontend.h |   29 ++
 linux/drivers/media/video/tuner-core.c          |  156 ++++++++++++++-
 linux/include/media/tuner.h                     |    6
 linux/include/media/v4l2-common.h               |    2
 v4l/Makefile                                    |    4
 v4l/scripts/gentree.pl                          |    1

All API changes on DVB are at the first patch:
	http://linuxtv.org/~mchehab/mrec2/hg_mrec_01.patch

It should be noticed that the comments at the patches may not be correct anymore, since I've folded some patches, and modified some API calls on Markus original series to be compatible with the way I did the integration on DVB frontend. If we go to this path, some work is still required.

I do frown upon code duplication, however, in this case it is a safer alternative to the one currently on the table. Earlier versions of the xc3028 tuner driver were bound to the video4linux tuner.ko module, for the sake of tuning analog television stations. There was a wrapper present inside the em2880-dvb driver that allowed the dvb subsystem to access the xc3028 via tuner.ko. I am not a big fan of this solution, however, it does not touch any core subsystem code. DVB-only devices can use a separate module in order to access the xc3028 without imposing dependencies on the v4l core.

Duplicating a driver is not a solution, just a terrible hack. We should focus on a way to use the same tuner driver for both Analog and Digital TV.

--
Cheers,
Mauro Carvalho Chehab
http://linuxtv.org
mchehab@xxxxxxxxxxxxx

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