On Monday 03 August 2015 20:48:28 Jarkko Nikula wrote: > On 08/03/2015 09:17 PM, Pali Rohár wrote: > > On Monday 03 August 2015 20:03:16 Jarkko Nikula wrote: > >> Hi > >> > >> On 08/01/2015 01:18 PM, Pali Rohár 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 > >> or how easy it would be to reproduce. > > > > Did you tested it on Nokia N900? Or other device? > > N900. Seems to be only user of TPA6130A2 in mainline :-) > Great, can you do more tests? I get this error often after I reboot N900 (without power off) more times. But no idea if this is just "sometimes". > >> 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? > > > > Stock Nokia's 2.6.28 kernel works always. With that kernel I have > > never seen this problem. So I do not think this is HW problem. > > > > This problem is there in more kernel versions, maybe in some older > > (like v3.5) is was there not so often. But do not remember > > correctly... > > It is well possible that some regression got introduced to TPA6130A2 > I2C 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. > Do you still have these pre 3.x kernels? This could be good starting point as 2.6.28 kernel is tooo old and heavily patches... > > Maybe some power management problem? Something is not always > > initialized correctly? > > > > I remember that there is some problem (maybe in NoLo - Nokia > > bootloader) that sometimes chainloaded U-Boot (booted via NoLo) is > > not able to initialize mmc chip (all read operation fails). In > > U-Boot I added some code to enable some parts in twl4030 regulator > > and after that mmc is working always... > > > > So maybe something similar? Kernel expects that some PM or > > regulator parts are initialized, but they are only sometimes? Just > > speculation... > > 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. We should know which devices are connected to which i2c bus. So maybe detecting which i2c device is incorrectly initialized? -- Pali Rohár pali.rohar@xxxxxxxxx
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