From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jarkko Nikula Subject: Re: Nokia N900 - audio TPA6130A2 problems Date: Mon, 03 Aug 2015 21:48:28 +0300 Message-ID: <55BFB77C.6000208@bitmer.com> References: <201507251228.27128@pali> <201508011218.45076@pali> <55BFACE4.1010100@bitmer.com> <201508032017.45654@pali> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <201508032017.45654@pali> Sender: linux-kernel-owner@vger.kernel.org To: =?UTF-8?B?UGFsaSBSb2jDoXI=?= Cc: Lars-Peter Clausen , Peter Ujfalusi , linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org, Pavel Machek , Sebastian Reichel , Aaro Koskinen , Tony Lindgren , Nishanth Menon , Ivaylo Dimitrov List-Id: linux-omap@vger.kernel.org On 08/03/2015 09:17 PM, Pali Roh=C3=A1r wrote: > On Monday 03 August 2015 20:03:16 Jarkko Nikula wrote: >> Hi >> >> On 08/01/2015 01:18 PM, Pali Roh=C3=A1r wrote: >>> On Saturday 25 July 2015 15:17:13 Lars-Peter Clausen wrote: >>> Hello, your patch did not helped. Problem is still there... >> >> For me v4.2-rc5 works, i.e. TPA6130A2 can still play loudly to >> headphones. Don't know were there any i2c etc regression before it o= r >> how easy it would be to reproduce. >> >=20 > Did you tested it on Nokia N900? Or other device? >=20 N900. Seems to be only user of TPA6130A2 in mainline :-) >> Logs below made me thinking can it be a HW issue? Although if it is >> an HW issue it shouldn't work sometimes I guess. Do you have any >> earlier well known configuration you could try is it an SW >> regression or something else? >> >=20 > Stock Nokia's 2.6.28 kernel works always. With that kernel I have nev= er=20 > seen this problem. So I do not think this is HW problem. >=20 > This problem is there in more kernel versions, maybe in some older (l= ike=20 > v3.5) is was there not so often. But do not remember correctly... > It is well possible that some regression got introduced to TPA6130A2 I2= C communication over the years without nobody than you now notices. We used to do QA back in Meego N900 days but that was pre 3.x kernels. > Maybe some power management problem? Something is not always initiali= zed=20 > correctly? >=20 > I remember that there is some problem (maybe in NoLo - Nokia bootload= er)=20 > that sometimes chainloaded U-Boot (booted via NoLo) is not able to=20 > initialize mmc chip (all read operation fails). In U-Boot I added som= e=20 > code to enable some parts in twl4030 regulator and after that mmc is=20 > working always... >=20 > So maybe something similar? Kernel expects that some PM or regulator=20 > parts are initialized, but they are only sometimes? Just speculation.= =2E. > I'm thinking the same. I could figure SCL could be stuck low if TPA or some other chip connected to the same I2C bus is without power and is pulling I2C signals down. --=20 Jarkko