From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:52550 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754693Ab2GXWMd (ORCPT ); Tue, 24 Jul 2012 18:12:33 -0400 Message-ID: <500F1DC5.1000608@iki.fi> Date: Wed, 25 Jul 2012 01:12:21 +0300 From: Antti Palosaari MIME-Version: 1.0 To: Michael Krufky CC: linux-media Subject: Re: tda18271 driver power consumption References: <500C5B9B.8000303@iki.fi> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 07/25/2012 12:55 AM, Michael Krufky wrote: > On Sun, Jul 22, 2012 at 3:59 PM, Antti Palosaari 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 -- http://palosaari.fi/