[alsa-devel] fsl_ssi.c: Getting channel slips with fsl_ssi.c in TDM (network) mode.
Nicolin Chen
nicoleotsuka at gmail.com
Tue Oct 27 21:11:02 CET 2015
On Tue, Oct 27, 2015 at 08:13:44AM +0100, Markus Pargmann wrote:
> > So, the dma priority doesn't seem to be the issue. It's now set in
> > the device tree, and strangely it's set to priority 0 (the highest)
> > along with the UARTS. priority 0 is just the highest in the device
> > tree -- it gets remapped to priority 3 in the sdma driver. the DT
> > exposes only 3 levels of DMA priority, low, medium, and high. I
> > created a new level that maps to DMA priroity 7 (the highest in the
> > hardware), but still got the problem.
> >
> > So, still something unknown causing dma to miss samples. must be in
> > the dma ISR I would assume. I guess it's time to look into that.
> Cc Nicolin, Fabio, Shawn
>
> Perhaps you have an idea about this?
Off the top of my head:
1) Enable TUE0, TUE1, ROE0, ROE1 to see if there is any IRQ trigged.
2) Set the watermarks for both TX and RX to 8 while using burst sizes
of 6. It'd be nicer to provisionally set these numbers using hard
code than your current change depending on fifo_depth as it might
be an odd value.
3) Try to enlarge the ALSA period size in the asound.conf or passing
parameters when you do the playback/capture so that the number of
interrupts from SDMA may reduce.
You may also see if the reproducibility is somehow reduced or not.
Nicolin
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