HELP:porting linux PXA audio driver to RTLinux(RTLinux core driver)

HELP:porting linux PXA audio driver to RTLinux(RTLinux core driver)

[nobin matthew]

Dear Friends,

              I am trying to port Linux PXA audio
driver to RTLinux. I am using pxa-ac7.c and
pxa-audio.c
 and eliminated sound_core.c, and i will register two
device /dev/mixer and /dev/dsp to RTLinux kernel.

           The real need is, i wants to generate a sin
wave using audio codec. With in 600us DMA controller
should fill the codec FIFO, if that is not met
distortion will happen. I think normal linux
interrupts and Process scheduling may cause some
problems.

In porting it seems difficult to port kernel
scheduling , dynamic memory allocation(for DMA) and
synchronization.

Please help me


Nobin Mathew

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Re: HELP:porting linux PXA audio driver to RTLinux(RTLinux core driver)

[Lee Revell]

On Fri, 2005-04-08 at 21:03 -0700, nobin matthew wrote:
> Dear Friends,
> 
>               I am trying to port Linux PXA audio
> driver to RTLinux. I am using pxa-ac7.c and
> pxa-audio.c
>  and eliminated sound_core.c, and i will register two
> device /dev/mixer and /dev/dsp to RTLinux kernel.
> 
>            The real need is, i wants to generate a sin
> wave using audio codec. With in 600us DMA controller
> should fill the codec FIFO, if that is not met
> distortion will happen. I think normal linux
> interrupts and Process scheduling may cause some
> problems.
> 
> In porting it seems difficult to port kernel
> scheduling , dynamic memory allocation(for DMA) and
> synchronization.

This is the exact same question you posted to linux-audio-dev.  And
you'll get the same answer here:

Don't waste your time with RTLinux.  Use a recent 2.6 kernel with Ingo's
realtime-preempt patches.  Configure with PREEMPT_RT.  This will provide
deterministic, hard realtime performance for any RT constraint down to
about 50 usecs.

RTLinux can meet a ~15 usec RT constraint, the RT preempt kernel will be
able to do this once the timer ISR is made preemptible again.

RTLinux is an obsolescent product that had its place in the 2.4 era but
is being superseded by a solution that's both technically superior and
100% free software.  Real time preemption is the future of hard realtime
on Linux.  All the major real time Linux players have recognized this,
even the ones who had competing solutions for 2.4 are porting their work
to the 2.6 RT-preempt framework.

Besides, RTLinux is a commercial product anyway.  If this project
requires use of RTLinux for political reasons, call your support rep.

Lee

Re: HELP:porting linux PXA audio driver to RTLinux(RTLinux core driver)

[Ian Campbell]

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On Fri, 2005-04-08 at 21:03 -0700, nobin matthew wrote:

> Please help me

It's a little bit rude to blanket CC so many lists with your requests,
and I'm quite sure linux-net has nothing whatsoever to do with audio.
They are also all lists dedicated to the regular version of Linux, not
RTLinux.

You should contact FSM labs for support with RTLinux.

Ian.
 
-- 
Ian Campbell

Be braver -- you can't cross a chasm in two small jumps.

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Re: HELP:porting linux PXA audio driver to RTLinux(RTLinux core driver)

[nitin ahuja]

Hi,

You cannot allocate memory in real time threads RTLinux's threads. You have to do it in the init_module function and pass the meory pointer to threads as parameter. 

Can you tell exactly what problem are you facing?

niTin