[alsa-devel] Driver code with mpc5200 pointer problem.

Jon Smirl jonsmirl at gmail.com
Mon May 4 15:22:22 CEST 2009

On Mon, May 4, 2009 at 9:00 AM, Mark Brown <broonie at sirena.org.uk> wrote:
> On Mon, May 04, 2009 at 08:58:04AM -0400, Jon Smirl wrote:
>> On Mon, May 4, 2009 at 8:43 AM, Takashi Iwai <tiwai at suse.de> wrote:
>> > Great. ?So can we remove BROKEN kconfig again?
>> Sure. There are only two current users of the driver and we know what
>> is going on.
> Could you expand on what you mean by "we know what is going on"?  If the
> driver is fixed then there shouldn't really be anything for anyone to
> know, the driver should just work.
> I wouldn't count on you being the only users - you may be the only
> people visibly talking about the driver in public but that's not quite
> the same thing as being the only users.

With the fix the driver is back to working the way it was before the
jiffies issue completely broke it.

But there are still problems in the driver. For example it is not
terminating streams correctly. I get a little burp of sound at the end
of stream that doesn't belong there.

I'm trying to fix the burp. How is stream termination supposed to
work? Right now when the driver gets STOP in the trigger function. It
immediately stops the DMA engine and resets the I2S channel. I'm not
clear on how this get synchronized in order to prevent the partial
transfer of a DMA period and allowing the FIFO time to drain.


Jon Smirl
jonsmirl at gmail.com

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