[Gta04-owner] Now that 3.2-final is out...

[Dr. H. Nikolaus Schaller]

Hi Neil,

Am 17.01.2012 um 06:41 schrieb NeilBrown:

> On Mon, 16 Jan 2012 08:37:08 +0100 Radek Polak <psonek2 at seznam.cz> wrote:
> 
>> On Sunday 15 January 2012 11:52:16 Neil Jerram wrote:
>> 
>>> Now, if I open the back cover and remove and replace the battery, the
>>> GTA04 boots up normally and fully.  So the problem above is not caused
>>> by low battery.
>>> 
>>> Any thoughts / ideas?  This is quite repeatable, so I could get
>>> diagnostics if you tell me how...
>> 
>> IIRC it was mentioned in some older mails that current 3.2 does not boot after 
>> halt command, because something is left initialized. You have to always 
>> completely power if off (remove battery), halt and reboot are for now not 
>> working.
> 
> It is definitely mentioned in
> 
>  http://projects.goldelico.com/p/gta04-kernel/page/Mainline-Status/#wikititle_34
> 
> Unfortunately it freezes before the serial ports are configured so I don't
> see any messages to help narrow it down.

Maybe a patch similar to this may help:

https://github.com/goldelico/gta04-kernel/commit/591a1ed250bcf4dd9de989f1a566a29e96469dd9

(I think it is incomplete resp. adds to another patch of kernel/printk.c ).

The idea is to bypass the kernel dmesg ring buffer completely and
flush each character asap. This allows to add printk before the serial
is initialized.

I have used this to debug NULL pointer dereferences in the backport
of the omap-serial.c driver to 2.6.32.

It makes booting much slower, but for debugging it is ok.

Nikolaus