Messages in this thread | | | Date | Mon, 22 Jun 2015 11:14:42 +0900 | Subject | Re: [PATCH] dmaengine: pl330: Really fix choppy sound because of wrong residue calculation | From | Krzysztof Kozłowski <> |
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2015-06-15 23:00 GMT+09:00 Krzysztof Kozlowski <k.kozlowski.k@gmail.com>: > 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. > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com> > Fixes: aee4d1fac887 ("dmaengine: pl330: improve pl330_tx_status() function") > Cc: <stable@vger.kernel.org> > Reported-by: gabriel@unseen.is > Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Gabriel, could you give this patch a try? It helped for my Odroid XU3, which has the same audio codec. Nevertheless it would be great to hear that it solves the initial bug report.
Best regards, Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in Please read the FAQ at http://www.tux.org/lkml/
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