[alsa-devel] DMA screams on MSP

Lee Jones lee.jones at linaro.org
Tue Feb 4 21:38:57 CET 2014

> >> I get this in my bootlog nowadays (v3.14-rc1):
> >>
> >> [    2.713897] dma dma0chan29: [d40_validate_conf] Invalid device type
> >> (14) physical channel exeeds available physical channels
> >
> > <snip>
> >
> >> (I patched dma40 to state the exact cause instead of just
> >> "invalid device type".)
> >>
> >> Like something (I guess ALSA SoC?) is trying real hard to get physical
> >> channel 14, but I can't seem to figure out what is going on.
> >>
> >> I will try to see if this also appears on the Snowball but I guess
> >> so?
> >>
> >> Any hints appreciated...
> >
> > It looks like you're attempting to initialise MSP2 (HDMI). Why are you
> > doing that? Can you `git grep msp2` and provide me with the output
> > please?
> This is just plain mainline, there is nothing special about my
> git tree...
> Yeah it appears I went in and marked msp2 "okay" in
> commit 70b41abc151f9 so that is causing it, I'll make a
> quick fix to get rid of that.
> But no matter whether it gets activated or not: should it not just
> work anyway? This message seems to suggest the DMA
> channel assignment is invalid.

I haven't tested/debugged any of the physical channels, so I don't
know what could be the particular issue. It should work in theroy, I
can't think what might have changed. The channel is the same, as are
the markers to use fixed physical channel. Do you have a copy of the
old Igloo or the internal ST-E Kernel? I'm pretty sure HDMI sound
worked in those.

Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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