[haiku-commits] Re: r34664 - haiku/trunk/src/add-ons/kernel/drivers/audio/hda
- From: Jérôme Duval <korli@xxxxxxxxxxxxxxxx>
- To: haiku-commits@xxxxxxxxxxxxx
- Date: Tue, 15 Dec 2009 10:52:46 +0100
2009/12/15 <ingo_weinhold@xxxxxx>:
> Author: bonefish
> Date: 2009-12-15 01:21:43 +0100 (Tue, 15 Dec 2009)
> New Revision: 34664
> Changeset: http://dev.haiku-os.org/changeset/34664/haiku
> Ticket: http://dev.haiku-os.org/ticket/4072
>
> Modified:
> haiku/trunk/src/add-ons/kernel/drivers/audio/hda/hda_controller.cpp
> Log:
> * stream_handle_interrupt(): Fixed a misunderstanding of the SDnLPIB (stream
> descriptor n link position in buffer) registers. They contain "the number
> of bytes that have been received off the link", which is not to be confused
> with the number of bytes that have been transferred by the DMA engine.
> The interrupt is triggered when the last byte of the buffer has been fetched
> by the DMA engine, at which point the stream's LPIB is still somewhere in
> the last buffer. So the interrupt handler could compute the wrong buffer
> index, which would lead to the multi audio add-on filling the wrong
> (currently being transferred) buffer, resulting in noisy sound. Now we use
> the DMA position. Should fix #4072.
Great it's working for you! I remember though reading that SDnLPIB
might still be of use on some ATI/VIA chipsets because the position
buffer is sometimes inaccurate. Maybe this patch fixes the nVidia hda
problem with the workaround I introduced.
I'll check today if playback and recording are still working correctly for me.
Bye,
Jérôme
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