Re: [Openvortex-dev] the loop problems

[Ryan Underwood]

Hi Manuel,

On Wed, Jul 02, 2003 at 09:32:16PM -0400, Manuel Jander wrote:
> Hi Ryan,
> 
> On Thu, 2003-07-03 at 01:05, Ryan Underwood wrote:
> > Hi Manuel,
> > 
> > On Wed, Jul 02, 2003 at 08:40:46PM -0400, Manuel Jander wrote:
> > > Hi,
> > > 
> > > On Wed, 2003-07-02 at 15:04, Ryan Underwood wrote:
> > > > Hi,
> > > > 
> > > > Perhaps we are having serialization issues in the read/write_codec
> > > > functions for the vortex?  I see in a lot of other ALSA drivers and
> > > > kernel drivers that the rmb/wmb/mb() functions are used whenever a tight
> > > > loop is going to be executed to ensure that everything is flushed out or
> > > > somesuch beforehand.
> > > > 
> > > 
> > > I just want to remind you that the Aureal cards use Bus Master DMA...
> > > There is no programmed IO audio data transfer. YOu set up the buffers
> > > and the rest is done by the card itself.
> > 
> > Is that true for the memory mapped I/O as well?
> 
> Well, as you said there can be problems with the MMIO used to write
> things to the codec for setup purposes. And it maybe that the stereo
> swapping is a problem of the codec setup rather than the audio data fed
> into the codec by the DMA engine.

Actually, I was thinking this might have something to do with the codec
issue, where the codec must be read back from a few times to ensure that
the proper data is returned.  I was thinking that perhaps writing to it
and then reading from it may end up happening out of order in the
hardware.

> Is there any chance to record the stereo swapping problem and send me
> audio sample ? I'm unable to reproduce that bug, and at leat knowing how
> it sounds like would help to try to guess whats really goind on.

Yes, I will do that soon.

> On the other hand, i'll try to update the technical data document, so
> that those people having that problem, maybe can figure out whats wrong.

Thanks!

-- 
Ryan Underwood, <nemesis at icequake.net>, icq=10317253