Messages in this thread | | | Date | Tue, 7 Jul 2015 09:30:50 +0530 | From | Vinod Koul <> | Subject | Re: [PATCH] dmaengine: pl330: Really fix choppy sound because of wrong residue calculation |
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On Mon, Jun 15, 2015 at 11:00:09PM +0900, Krzysztof Kozlowski wrote: > When pl330 driver was used during sound playback, after some time or > after a number of plays the sound became choppy or totally noisy. For > example on Odroid XU3 board the first four executions of aplay with > small WAVE worked fine, but fifth was unrecognizable with errors: > $ aplay /usr/share/sounds/alsa/Front_Right.wava > underrun!!! (at least 0.095 ms long) > > Issue was caused by wrong residue reported by pl330 driver to > pcm_dmaengine for its cyclic dma transfers. > > The pl330_tx_status(), residue reporting function, used a "last" flag in > a descriptor to indicate that there is no more data to send. > > The pl330_tx_submit() iterated over descriptors trying to remove this > flag from them and then mark last descriptor as "last". However when > iterating it actually removed the flag not from descriptors but always > from last of it (and then reset it). Thus effectively once some > descriptor was marked as last, then it stayed like this forever causing > residue to be reported too low.
Applied, thanks
-- ~Vinod
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