[Gta04-owner] Kernel 3.14-rc5 for GTA04

Dr. H. Nikolaus Schaller hns at goldelico.com
Fri Mar 7 18:00:07 CET 2014


Am 07.03.2014 um 17:41 schrieb mx4812 at arcor.de:

> 
> 
>>> Did you check if the delay loop is correctly calibrated?
>>> Somewhere the kernel says: "Calibrating delay loop" and prints out
>>> some value: lpj=11969856
>> 
>> here is the 3.14 kernel
>> [    0.001495] Calibrating delay loop... 594.73 BogoMIPS (lpj=2973696)
>> 
>> and here the 3.12 kernel
>> 
>> [    0.000274] Calibrating delay loop... 319.48 BogoMIPS (lpj=1597440)

And the SD card with the 3.12 kernel on the board where I did test the 3.14:

[    0.000305] Calibrating delay loop... 334.23 BogoMIPS (lpj=1671168)

So there is a small difference - as expected. But not the factor 2.

> 
> I remember from previous notebooks that I used that such timings also had the tendency
> to get messed up after resume events (slugishness and slooweerr soouunnd aaoouutpuut).

Interesting!

It may also explain why the OTG port is detecting a cable but not working. If some clock
is not initialized correctly it is simply not running the USB protocols correctly.

What makes me wonder a lot is why it is different at all.

It is the same hardware and the same message right at the beginning of a fresh boot (not
even a resume).

And I have not found a significant patch or diff to 3.12.7 - where it works.

The only difference is that we now boot with device tree and have no board file
(well, we use the board-generic.c instead of board-gta04.c).

But I *assume* that since the device tree works on other OMAP3 boards
(e.g. BeagleBoard), that it should not be the reason.

Another change could be in the kernel config.

BR,
Nikolaus

 


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