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.
Regards,
Mike
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