Re: [Jack-Devel] Jack on a Nexus 7

Just to clarify, the bus error occurred in the initialization of
engine->control->frame_timer in jack_engine_new. I apologize that that I
lost track of the exact line of code.after I diagnosed the problem as an
ARM alignment issue and corrected it by unpacking the structure.

Brad


On Sun, Jul 21, 2013 at 10:23 AM, Christian Schoenebeck <
[hidden]> wrote:

> On Sunday 21 July 2013 16:43:44 Chris Caudle wrote:
> > On Sun, July 21, 2013 8:45 am, Christian Schoenebeck wrote:
> > > I doubt that the crash you got is caused by packed data structures.
> > > Disabling the packed attributes most probably just moved the symptoms.
> >
> > Non-aligned memory access is not supported on ARM.  This was discussed
> > fairly extensively on the list a few months  back, should be in the
> > archives.  I think currently Jack2 does not pack structs on ARM to solve
> > that problem.
>
> Well, the Nexus 7 provides an ARMv7 CPU with hardware supported non-aligned
> access. But on the other hand, I just figured that there are still
> instructions like double word (64 bit) access which raise an alignment
> fault
> (section A3.2.1 in the ARM Architecture Reference Manual). So far I thought
> those alignment faults would be caught & processed correctly by the OS
> (similar like software implemented unaligned simple loads/saves on ARMv6
> systems), but I must admit I am not sure if that's always the case.
>
> CU
> Christian
> 
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