Re: tda18271 driver power consumption

[Antti Palosaari <crope@iki.fi>]

On 07/25/2012 12:55 AM, Michael Krufky wrote:
> On Sun, Jul 22, 2012 at 3:59 PM, Antti Palosaari <crope@iki.fi> wrote:
>> Moi Michael,
>> I just realized tda18271 driver eats 160mA too much current after attach.
>> This means, there is power management bug.
>>
>> When I plug my nanoStick it eats total 240mA, after tda18271 sleep is called
>> it eats only 80mA total which is reasonable. If I use Digital Devices
>> tda18271c2dd driver it is total 110mA after attach, which is also quite OK.
>
> Thanks for the report -- I will take a look at it.
>
> ...patches are welcome, of course :-)

I suspect it does some tweaking on attach() and chip leaves powered (I 
saw demod debugs at calls I2C-gate control quite many times thus this 
suspicion). When chip is powered-up it is usually in some sleep state by 
default. Also, on attach() there should be no I/O unless very good 
reason. For example chip ID is allowed to read and download firmware in 
case it is really needed to continue - like for tuner communication.


What I found quickly testing few DVB USB sticks there seems to be very 
much power management problems... I am now waiting for new multimeter in 
order to make better measurements and likely return fixing these issues 
later.

regards
Antti

-- 
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