Re: [PATCH 2/3] dvb-usb: multi-frontend support (MFE)

[Antti Palosaari <crope@iki.fi>]

On 07/28/2011 01:07 AM, Malcolm Priestley wrote:
> On Wed, 2011-07-27 at 16:06 -0300, Mauro Carvalho Chehab wrote:
>> Em 25-07-2011 21:17, Antti Palosaari escreveu:
>>> Signed-off-by: Antti Palosaari<crope@iki.fi>

>>> +            adap->fe[i] = NULL;
>>> +            /* In error case, do not try register more FEs,
>>> +             * still leaving already registered FEs alive. */
>>
>> I think that the proper thing to do is to detach everything, if one of
>> the attach fails. There isn't much sense on keeping the device partially
>> initialized.
>>
>> From memory, I recall the existing code doesn't detach the frontend even
> if the device driver forces an error. So, the device driver must detach
> the frontend first.

Yes, if you return for example error (or fe == NULL) for .tuner_attach() 
it does not detach or deregister it - just silently discard all. I 
thought very many times those when implementing this and keep very 
careful not to change old functionality.

> The trouble is that dvb-usb is becoming dated as new drivers tend to
> work around it. No one likes to touch it, out of fear of breaking
> existing drivers.

Yes, so true. I have thought that too. There is a lot of things I want 
to change but those are very hard without massive work.

* We should have priv at the very first. No priv for FW DL example.
* Remote keytable should be property of certain device model not adapter
* There should be way to set count of adapter (and fe) in runtime (this 
is why I allowed to fail 2nd FE attach silently)
* no probe (read eeprom etc) callback (I think read MAC could be renamed 
for probe)
* no FE power control (GPIOs etc) that MFE patch adds this too
* maybe probe1 and probe2 callbacks needed. sequence something like plug 
device => probe1 => download FW => probe2 => attach demod


> I think perhaps some kind of legacy wrapper is needed here, with the
> moving of dvb-usb to its own core, so more development work can be done.

Wish like to thank you these comments Malcolm!

regards
Antti

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