Re: [RFC] file tree rearrangement - was: Re: [RFC PATCH 0/3] Improve Kconfig selection for media devices

Hans Verkuil <hverkuil@xxxxxxxxx> · Mon, 28 May 2012 11:42:20 +0200

On Sun May 27 2012 22:15:08 Mauro Carvalho Chehab wrote:
> Em 27-05-2012 15:47, Andy Walls escreveu:
> > Hans Verkuil <hverkuil@xxxxxxxxx> wrote:
> > 
> >> On Sun May 27 2012 19:13:38 Mauro Carvalho Chehab wrote:
> >>> Em 27-05-2012 13:56, Mauro Carvalho Chehab escreveu:
> >>>> The Kconfig building system is improperly selecting some drivers,
> >>>> like analog TV tuners even when this is not required.
> >>>>
> >>>> Rearrange the Kconfig in a way to prevent that.
> >>>>
> >>>> Mauro Carvalho Chehab (3):
> >>>>   media: reorganize the main Kconfig items
> >>>>   media: Remove VIDEO_MEDIA Kconfig option
> >>>>   media: only show V4L devices based on device type selection
> >>>>
> >>>>  drivers/media/Kconfig               |  114
> >> +++++++++++++++++++++++------------
> >>>>  drivers/media/common/tuners/Kconfig |   64 ++++++++++----------
> >>>>  drivers/media/dvb/frontends/Kconfig |    1 +
> >>>>  drivers/media/radio/Kconfig         |    1 +
> >>>>  drivers/media/rc/Kconfig            |   29 ++++-----
> >>>>  drivers/media/video/Kconfig         |   76 +++++++++++++++++------
> >>>>  drivers/media/video/m5mols/Kconfig  |    1 +
> >>>>  drivers/media/video/pvrusb2/Kconfig |    1 -
> >>>>  drivers/media/video/smiapp/Kconfig  |    1 +
> >>>>  9 files changed, 181 insertions(+), 107 deletions(-)
> >>>>
> >>>
> >>> The organization between DVB only, V4L only and hybrid devices are
> >> somewhat
> >>> confusing on our tree. From time to time, someone proposes changing
> >> one driver
> >>> from one place to another or complains that "his device is DVB only
> >> but it is
> >>> inside the V4L tree" (and other similar requests). This sometimes
> >> happen because
> >>> the same driver can support analog only, digital only or hybrid
> >> devices.
> >>>
> >>> Also, one driver may start as a DVB only or as a V4L only and then 
> >>> it can be latter be converted into an hybrid driver.
> >>>
> >>> So, the better is to rearrange the drivers tree, in order to fix this
> >> issue,
> >>> removing them from /video and /dvb, and storing them on a better
> >> place.
> >>>
> >>> So, my proposal is to move all radio, analog TV, digital TV, webcams
> >> and grabber
> >>> bridge drivers to this arrangement:
> >>>
> >>> drivers/media/isa - ISA drivers
> >>> drivers/media/usb - USB drivers
> >>> drivers/media/pci - PCI/PCIe drivers
> >>> drivers/media/platform - platform drivers
> >>
> >> drivers/media/parport
> >> drivers/media/i2c
> >>
> >> Also, if we do this then I would really like to separate the sub-device
> >> drivers
> >>from the main drivers. I find it very messy that those are mixed.
> >>
> >> So: drivers/media/subdevs
> >>
> >> We might subdivide /subdevs even further (sensors, encoders, decoders,
> >> etc.) but
> >> I am not sure if that is worthwhile.
> >>
> >> Frankly, the current directory structure (other than the lack of a
> >> subdevs
> >> directory) doesn't bother me. But your proposal is a bit cleaner.
> >>
> >> Regards,
> >>
> >> 	Hans
> >>
> >>>
> >>> Comments?
> >>>
> >>> Regards,
> >>> Mauro
> >>>
> >>> -
> >>>
> >>> PS.: for now, I don't intend to touch at I2C/ancillary drivers. We
> >> may latter move
> >>> the i2c drivers that aren't frontend/tuners to media/i2c or to
> >> media/common.
> >>> --
> >>> 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
> >>>
> >> --
> >> 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
> > 
> > Also
> > 
> > cx2341x and tveeprom
> 
> cx2341x is a sub-device module. So, it can go to drivers/media/subdevs
> (ok, it has other problems, but solving them is not as simple as moving
> things from one place to the other - so let's not mix it here).

It's not a subdev. It's a helper module, so it should go to common (or 'helpers').

> The case of tveeprom is different, because it is not really a sub-device.
> 
> Btw, this file is bad named - it should be called hauppauge-eeprom or
> something like that. Yet, I wouldn't move it out of drivers/media/video
> (or at least on this first step).
> 
> There are other similar cases. for example, btcx-risc is a common module
> used by both cx88 and bttv drivers to handle the RISC processor that
> exists on both. This is not a sub-device, so it won't fit on the above
> structure. . 
> 
> Maybe we can create a drivers/media/v4l2-core and move everything that
> belongs to the core into it, and the things that won't fit elsewhere
> can be moved into drivers/media/common.

Ack.

> I would also move tuner, dvb-core and frontend to an upper level:
> 
> So, in summary, the final structure would be:
> 
> drivers/media
> 	/common		- drivers that are "common" to several ones, like tveeprom and btcx-risc

And saa7146 sources in /common/saa7146. That will (finally!) make sense.

What can go in here:

- saa7146
- tveeprom
- cx2341x
- btcx-risc
- radio-isa
- smiapp-pll (?)

We should probably also try and get tea575x-tuner.c in here. But that can be
done in a separate step.

> 	/dvb-core	- what is already at dvb/dvb-core
> 	/frontends	- what is already at dvb/frontends
> 	/isa		- all ISA drivers
> 	/parport	- all parallel port drivers

I propose to replace /parport with a /others directory for things of which we
have only a very few (parport, i2c) or are hard to classify (si470x, vivi,
mem2mem_testdev).

> 	/pci		- all PCI/PCIe drivers
> 	/platform	- all platform drivers
> 	/subdevice	- all sub-device drivers

Either /subdevices or /subdevs. It should definitely be plural.

> 	/tuner		- what's currently at common/tuners

Ditto: /tuners

> 	/usb		- all USB drivers
> 	/v4l2-core	- V4L2 core

/media-core for the media*.c sources.

> 
> After doing that, the Kconfig options at isa, parport, pci, platform and usb
> can be optimized further, based on the media support "filters":
> 
> <m>  Multimedia support  --->
>     [ ]   Webcams and video grabbers support
>     [ ]   Analog TV support
>     [ ]   Digital TV support
>     [ ]   AM/FM radio receivers/transmitters support
>     [ ]   Remote Controller support 

One thing wasn't clear to me: if I have a hybrid device I gathered that it be enabled
only if both analog and digital are set, right? But is that also true for radio and RC
support? So if I have a card with all of the above, will it be enabled only if I check
all four items?

That doesn't really make sense to me. I think the average end-user just cares about the
hardware that he wants to enable, and if a hybrid device is selected, then that should
select all the various core configs that it needs. Not the other way around.

Another thing: I would move 'video grabber' away from webcams and to 'Analog TV/Video support'.
And rename 'Digital TV' to 'Digital TV/Video' as well. A video grabber driver has much more to
do with TV then it does with webcams.

But basically I would do away with filters altogether and just present a menu with bus
type (usb/pci/platform/isa/others) and subdivide each bus either by captions:

*** Webcams ***
*** Analog TV/Video Capture ***

or corresponding submenus. This could be decided based on the number of devices in each
category.

Regards,

	Hans
--
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