Re: [PATCH 03/10] V4L/DVB: tda18271: Add some hint about what tda18217 reg ID returned

[Mauro Carvalho Chehab <mchehab@redhat.com>]

Em 30-09-2010 15:57, Michael Krufky escreveu:
> On Tue, Sep 28, 2010 at 2:46 PM, Mauro Carvalho Chehab
> <mchehab@redhat.com> wrote:
>> Instead of doing:
>>
>> [   82.581639] tda18271 4-0060: creating new instance
>> [   82.588411] Unknown device detected @ 4-0060, device not supported.
>> [   82.594695] tda18271_attach: [4-0060|M] error -22 on line 1272
>> [   82.600530] tda18271 4-0060: destroying instance
>>
>> Print:
>> [  468.740392] Unknown device (0) detected @ 4-0060, device not supported.
>>
>> for the error message, to help detecting what's going wrong with the
>> device.
>>
>> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
>>
>> diff --git a/drivers/media/common/tuners/tda18271-fe.c b/drivers/media/common/tuners/tda18271-fe.c
>> index 7955e49..77e3642 100644
>> --- a/drivers/media/common/tuners/tda18271-fe.c
>> +++ b/drivers/media/common/tuners/tda18271-fe.c
>> @@ -1177,7 +1177,7 @@ static int tda18271_get_id(struct dvb_frontend *fe)
>>                break;
>>        }
>>
>> -       tda_info("%s detected @ %d-%04x%s\n", name,
>> +       tda_info("%s (%i) detected @ %d-%04x%s\n", name, regs[R_ID] & 0x7f,
>>                 i2c_adapter_id(priv->i2c_props.adap),
>>                 priv->i2c_props.addr,
>>                 (0 == ret) ? "" : ", device not supported.");
> 
> A patch like this is fine for testing, but I see no reason for merging
> this into the kernel.  Can you provide an explaination as per why this
> would be useful?  In general, if you see, "Unknown device detected @
> X-00YY, device not supported." then it means that this is not a
> tda182x1.

cx231xx have 4 I2C buses. The device I'm working with have the tuner at the wrong chip.
As it doesn't support 0 byte transactions, if you try to read from the wrong i2c, it will
just return 0 to all read requests.

So, this kind of message can be very useful if someone sends us a report about a new device.
The changes are small and are printed only in the case of errors, where people will likely
try to reach the developers. So, I think it is a good idea to have it mainstream.

Cheers,
Mauro