[alsa-devel] [PATCH 2/6] ASoC/mpc5200: get rid of the appl_ptr tracking nonsense
broonie at opensource.wolfsonmicro.com
Wed Nov 11 21:03:22 CET 2009
On 11 Nov 2009, at 19:24, Grant Likely <grant.likely at secretlab.ca>
> On Wed, Nov 11, 2009 at 11:37 AM, Mark Brown
> <broonie at opensource.wolfsonmicro.com> wrote:
>> On Wed, Nov 11, 2009 at 11:38:06AM -0500, Jon Smirl wrote:
>>>> Providing a final valid data point to the driver would possibly
>>>> make things worse since if it were used then you'd have the
>>>> race where the application has initialized some data but not yet
>>>> to update the driver to tell it it's being handed over; if the
>>> That's an under run condition.
>> Yes, of course - the issue is that this approach encourages them,
>> the system less robust if things are on the edge. The mpc5200
>> seems to
>> be not just on the edge but comfortably beyond it for some reason.
> I can't reproduce the issue at all as long at the dev_dbg() statement
> in the trigger stop path is disabled. With it enabled, I hear the
> problem every time. The 5200 may not be a speedy beast, but it is
> plenty fast enough to shut down the audio stream before stale data
> starts getting played out.
Yes, that does sound entirely consistent with the problem being a
latency issue if you're sending the dev_dbg() output to the serial
port. I'd be surprised if it were anything else to be honest.
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