From mboxrd@z Thu Jan  1 00:00:00 1970
From: sudhakar.raj@ti.com (Sudhakar Rajashekhara)
Date: Tue, 25 May 2010 18:58:19 +0530
Subject: [PATCH 3/6] davinci: edma: clear events in edma_start()
In-Reply-To: <4BFBA100.4020805@windriver.com>
References: <1268841163-5868-1-git-send-email-khilman@deeprootsystems.com>	<1268841163-5868-4-git-send-email-khilman@deeprootsystems.com>	<4BFA6A22.1000006@windriver.com>	<871vd16wic.fsf@deeprootsystems.com>
	<4BFBA100.4020805@windriver.com>
Message-ID: <00f701cafc0e$23dedbf0$6b9c93d0$@raj@ti.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi Stanley,

On Tue, May 25, 2010 at 15:35:52, stanley.miao wrote:
> Kevin Hilman wrote:
> > <snip>
> >>>
> >>>       
> >> This patch causes that the sound can not work normally on OMAP_L138.
> >>
> >>     
> >
> > Can you describe "can not work normally"?  Does that mean simply does
> > not work, or works with pops & clicks etc.?
> >
> > Just to clarify... how did you isolate it to this patch.
> >
> > If you revert just this patch on current davinci git, do you have
> > working sound as you expect again?
> >   
> Below is the test result:
> 
> $/root> aplay audiodump.wav
> Playing WAVE 'audiodump.wav' : Signed 16 bit Little Endian, Rate 44100 
> Hz, Stereo
> aplay: pcm_write:1269: write error: Input/output error
> $/root>
> 
> After revert it, the audio works fine.
> 

This patch works fine on DM644x which has McBSP but breaks audio on OMAP L138
(as you had mentioned) which has McASP. Ideally McBSP/McASP should start after
EDMA is started. If not then this patch clears the EDMA event which is actually
set by McBSP/McASP. As this patch is working fine on DM644x, I think there is
some issue in the audio driver which needs to be debugged.

Regards,
Sudhakar