From mboxrd@z Thu Jan  1 00:00:00 1970
From: Grant Likely <grant.likely@secretlab.ca>
Subject: Re: [PATCH] ASoC: MPC5200: Support for buffer wrap
	around
Date: Fri, 31 Jul 2009 19:57:34 -0600
Message-ID: <fa686aa40907311857j6c1f14eftcee349f693eaa3ed@mail.gmail.com>
References: <20090731230311.17686.46431.stgit@riker>
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To: John Bonesio <bones@secretlab.ca>
Cc: Grant Likely <grant.likely@secretlab.ca>, alsa-devel@alsa-project.org, Mark Brown <broonie@opensource.wolfsonmicro.com>, Eric Millbrandt <emillbrandt@dekaresearch.com>
List-Id: alsa-devel@alsa-project.org

On Friday, July 31, 2009, John Bonesio <bones@secretlab.ca> wrote:
> We've encountered strange behavior in the alsamixer settings using the wm=
9712
> codec. If we unmute the headphone output and then unmute the PCM output, =
the
> headphone output gets reset to mute in the hardware register. At this poi=
nt
> the hardware register does not match the value in the register cache.
>
> I've spent some time debugging this, and the headphone setting is set out=
side
> of any code path that would call the ac97_write() routine. As best as I c=
an
> tell, there is something strange going on in hardware.
>
> I've provided this patch that works around the problem.
>
> Have any of you seen this before? Is this patch the right approach?
>
> - John
>
> The code in psc_dma_bcom_enqueue_tx() didn't account for the fact that
> s->runtime->control->appl_ptr can wrap around to the beginning of the
> buffer. This change fixes this problem.
>
> Signed-off-by: John Bonesio <bones@secretlab.ca>

Hey John,

It would appear that you've attached the wrong patch.

g.

> ---
>
> =A0sound/soc/fsl/mpc5200_dma.c | =A0 17 +++++++++++++++++
> =A01 files changed, 17 insertions(+), 0 deletions(-)
>
> diff --git a/sound/soc/fsl/mpc5200_dma.c b/sound/soc/fsl/mpc5200_dma.c
> index cfe0ea4..2551c58 100644
> --- a/sound/soc/fsl/mpc5200_dma.c
> +++ b/sound/soc/fsl/mpc5200_dma.c
> @@ -70,6 +70,23 @@ static void psc_dma_bcom_enqueue_next_buffer(struct ps=
c_dma_stream *s)
>
> =A0static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s)
> =A0{
> + =A0 =A0 =A0 if (s->appl_ptr > s->runtime->control->appl_ptr) {
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 /*
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0* In this case s->runtime->control->appl=
_ptr has wrapped around.
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0* Play the data to the end of the bounda=
ry, then wrap our own
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0* appl_ptr back around.
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0*/
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 while (s->appl_ptr < s->runtime->boundary) {
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 if (bcom_queue_full(s->bcom=
_task))
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 return;
> +
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 s->appl_ptr +=3D s->period_=
size;
> +
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 psc_dma_bcom_enqueue_next_b=
uffer(s);
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 }
> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 s->appl_ptr -=3D s->runtime->boundary;
> + =A0 =A0 =A0 }
> +
>  =A0 =A0 =A0 =A0while (s->appl_ptr < s->runtime->control->appl_ptr) {
>
>  =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0if (bcom_queue_full(s->bcom_task))
>
>

-- =

Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.