On 09/07/2011 08:45 PM, Michael Krufky wrote:
On Wed, Sep 7, 2011 at 1:41 PM, Michael Krufky<mkrufky@xxxxxxxxxxxxxx> wrote:
On Wed, Sep 7, 2011 at 12:51 PM, Antti Palosaari<crope@xxxxxx> wrote:
On 08/01/2011 05:24 AM, Mauro Carvalho Chehab wrote:
Em 31-07-2011 22:22, Antti Palosaari escreveu:
On 08/01/2011 03:46 AM, Mauro Carvalho Chehab wrote:
One bad thing I noticed with the API is that it calls
adap->props.frontend_attach(adap)
several times, instead of just one, without even passing an argument for
the driver to
know that it was called twice.
IMO, there are two ways of doing the attach:
1) call it only once, and, inside the driver, it will loop to add the
other FE's;
2) add a parameter, at the call, to say what FE needs to be initialized.
I think (1) is preferred, as it is more flexible, allowing the driver to
test for
several types of frontends.
I am planning to change DVB USB MFE call .frontend_attach() only once. Is
there any comments about that?
Currently there is anysee, ttusb2 and cx88 drivers which uses MFE and change
is needed ASAP before more MFE devices are coming.
Also .num_frontends can be removed after that, since DVB USB will just loop
through 0 to MAX FEs and register all FEs found (fe pointer !NULL).
CURRENTLY:
==========
.frontend_attach()
if (adap->fe_adap[0].fe == NULL)
adap->fe_adap[0].fe = dvb_attach(DVB-T)
else if (adap->fe_adap[1].fe == NULL)
adap->fe_adap[1].fe = dvb_attach(DVB-C)
else if (adap->fe_adap[2].fe == NULL)
adap->fe_adap[2].fe = dvb_attach(DVB-S)
PLANNED:
========
.frontend_attach()
adap->fe_adap[0].fe = dvb_attach(DVB-T)
adap->fe_adap[1].fe = dvb_attach(DVB-C)
adap->fe_adap[2].fe = dvb_attach(DVB-S)
Antti,
I don't understand exactly what you are proposing -- Is this a change
for the anysee driver? ...or is it a change for the dvb-usb
framework? ...or is it a change to dvb-core, and every driver in the
subsystem?
In the anysee driver, I see that you are using this:
.frontend_attach()
if (adap->fe_adap[0].fe == NULL)
adap->fe_adap[0].fe = dvb_attach(DVB-T)
else if (adap->fe_adap[1].fe == NULL)
adap->fe_adap[1].fe = dvb_attach(DVB-C)
else if (adap->fe_adap[2].fe == NULL)
adap->fe_adap[2].fe = dvb_attach(DVB-S)
I have no problem if you want to change the anysee driver to remove
the second dvb_usb_adap_fe_props context, and replace with the
following:
.frontend_attach()
adap->fe_adap[0].fe = dvb_attach(DVB-T)
adap->fe_adap[1].fe = dvb_attach(DVB-C)
adap->fe_adap[2].fe = dvb_attach(DVB-S)
I believe this will work in the anysee driver for you, even with my
changes that got merged yesterday... However, I do *not* believe that
such change should propogate to the dvb-usb framework or dvb-core
itself, because it can have a large negative impact on the drivers
using it.
For example, my mxl111sf driver was merged yesterday. Since it is the
initial driver merge, it currently only supports one frontend (ATSC).
The device also supports two other delivery systems, and has two
additional dtv demodulators, each attached via a separate input bus to
the USB device, each streaming on a separate USB endpoint.
Many demod drivers do an ID test or some other kind of initialization
during the _attach() function. A device like the mxl111sf would have
to manipulate the USB device state and alter the bus operations before
and after each frontend attachment in order for the _attach() calls to
succeed, not to mention the separate calls needed for bus negotiation
to power on the correct demodulator and initialize its streaming data
path.
I repeat, if this is a change that is specific to your anysee driver,
then it seems like a good idea to me. However, if your plan is to
change dvb-usb itself, and / or dvb-core, then I'd really like to have
a better idea of the implications that this change will bring forth.
So, to help reduce the confusion, can you clarify exactly what code
you plan to change, and what impact it will have on the drivers that
exist today?
Best Regards,
Michael Krufky
ADDENDUM:
For the anysee driver, for your single .frontend_attach()
adap->fe_adap[0].fe = dvb_attach(DVB-T)
adap->fe_adap[1].fe = dvb_attach(DVB-C)
adap->fe_adap[2].fe = dvb_attach(DVB-S)
...for this to work in today's dvb-usb code without modification to
the dvb-usb framework, i believe that you should do a test for
(adap->fe_adap[0].fe&& adap->fe_adap[1].fe&& adap->fe_adap[2].fe )
... if null, then attach, if not null, then exit -- this will prevent
the second context's initialization from occurring twice.
Yes, I now saw when looked latest anysee driver that you moved
.streaming_ctrl(), .frontend_attach() and .tuner_attach() to frontend
property. OK, it is not then relevant anymore to change register all as
once.
What is size_of_priv used?
regards
Antti
--
http://palosaari.fi/
--
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
