On Sunday 15 March 2009 18:28:42 Trent Piepho wrote:
> On Sun, 15 Mar 2009, Hans Verkuil wrote:
> > On Sunday 15 March 2009 17:04:43 Trent Piepho wrote:
> > > On Sun, 15 Mar 2009, Hans Verkuil wrote:
> > > > Hi Mauro,
> > > >
> > > > Can you review my ~hverkuil/v4l-dvb-bttv2 tree?
> > >
> > > It would be a lot easier if you would provide patch descriptions.
> >
> > Here it is:
> >
> > - bttv: convert to v4l2_subdev.
>
> You aren't even trying. I could easily write two pages on this patch.
You are right. Mauro already knew about all this, but since I posted it to
linux-media as well I should have given a more detailed explanation.
Here we go:
> What new module parameters did you add?
tvaudio to override the 'needs_tvaudio' from the card definition.
> Why?
Since just modprobing a module manually will no longer work when the i2c
autoprobing mechanism disappears. So you need a method to override it.
The main reason for doing this is if the card definition is incorrect.
> What module parameters did
> you delete?
autoload
> Why?
You will always autoload, so it has become meaningless.
> How does one translate a existing modprobe.conf file?
Remove the autoload option.
> Why are the i2c addresses from various i2c chips moved into the bttv
> driver?
It is now the adapter driver that tells the i2c core where to probe instead
of the other way around. The reason is that it is the adapter driver who
has the knowledge where i2c chips are.
> Doesn't it make more sense that the addresses for chip X should
> be in the driver for chip X?
I do not want to make too many changes, but when all v4l drivers are
converted I will revisit this issue. I'm thinking of adding an inline
function like this in the header belonging to each i2c driver (in
include/media):
static inline const unsigned short *tvaudio_addrs(void)
{
static const unsigned short addrs[] = { ... };
return addrs;
}
Then you can use that in the adapter driver. It's only relevant if you do
not know the exact address, since it is always better to use that if you
know it.
>
> How has module loading changed? Can one no longer *not* autoload modules
> if you are trying to test drivers that are not installed in /lib/modules?
The adapter driver initiates loading of the i2c modules and probes for and
attaches to the i2c devices. Just doing 'modprobe foo' will no longer cause
it to attach to any i2c adapter.
> What fields did you add to the card database?
has_saa6588.
> Why?
Bttv relied on the user to do 'modprobe saa6588' manually. Which no longer
works.
> How much did the size increase?
No idea. Let me see:
Old:
text data bss dec hex filename
69915 14044 756 84715 14aeb v4l/bttv.ko
New:
text data bss dec hex filename
71177 14168 756 86101 15055 v4l/bttv.ko
> What is the never set has_saa6588 field in tvcards needed
> for?
Any card with a saa6588 can set it. Currently the only board that has it is
the Terratec Active Radio Upgrade, which is an addon and is detected
separately.
> What are the parameters to bttv_call_all?
It's a small macro for the v4l2_device_call_all() utility (see
v4l2-framework.txt for more info on that):
#define bttv_call_all(btv, o, f, args...) \
v4l2_device_call_all(&btv->c.v4l2_dev, 0, o, f, ##args)
> How did you change the probing sequence? What was it before? What is it
> now?
It was random (dependent on the load order of the modules). Now it is in the
order as they are probed in bttv-cards.c:
1) tuner (really three: radio tuner, demod, tv tuner)
2) saa6588
3) msp3400
4) tvaudio
5) tda7432
Since tvaudio now supports tda9875 (it's in my pending pull request, not yet
merged in the master) bttv no longer attempts to load the tda9875 module.
It was much easier to tell the tda9875 and tda9874 apart if they were
implemented in the same module. We should probably merge tda7432 into
tvaudio as well later on.
>
> Where do the subdevs you created get deleted?
When the i2c adapter is deleted or when the v4l2_device is unregistered,
whichever comes first. When the i2c client is removed they unregister
themselves from the list in v4l2_device automatically (but this might
change in the future as it relies on the fact that deleting the i2c adapter
will also delete the i2c clients). And when the v4l2_device is unregistered
it will unregister all its subdevices as well.
Regards,
Hans
--
Hans Verkuil - video4linux developer - sponsored by TANDBERG
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