[alsa-devel] Intel SST on a Bay Trail tablet

[Vinod Koul]

On Tue, Apr 14, 2015 at 05:06:27PM +0300, Jarkko Nikula wrote:
> My 2c below.
> 
> On 04/14/2015 04:02 PM, Antonio Ospite wrote:
> >On Wed, 4 Mar 2015 17:02:18 +0100
> >Antonio Ospite <ao2 at ao2.it> wrote:
> 
> >I realized than I needed to set up the path between the FrontEnd DAI
> >and the BackEnd one, and in fact the error below goes away and I can
> >_start_ some playback after switching on these controls:
> >	codec_out1 mix 0 pcm0_in Switch
> >	media0_out mix 0 media1_in Switch
> >which AFAICS constitute the playback path.
> >
> >However there is still no sound, and the playback stalls, and the
> >interrupt count suddenly stops for the intel_sst_driver IRQ
> >(in /proc/interrupts).
> >
> What comes to my mind did you change .acpi_ipc_irq_index = 5 to 0
> zero in sound/soc/intel/sst/sst_acpi.c: byt_rvp_res_info structure?
> 
> According to Teclast's DSDT table the DSP-host interrupt is at first
> interrupt resource index.
> 
> >By looking at /sys/kernel/debug under Android it looks like the
> >codec is connected to SSP2, and not SSP0 as we imagined before:
> >/sys/kernel/debug/asoc/baytrailaudio/sst-platform/dapm/ssp2 playback
> >/sys/kernel/debug/asoc/baytrailaudio/sst-platform/dapm/ssp2 Capture
> >
> >So now I'd like to make sure the mixer settings are OK before looking
> >elsewhere again.
> >
> >Vinod, Subhransu, or anyone else, can you share some working alsa state
> >files for the baytrailcraudio device in linux mainline?
> >
> Question to Vinod et all too:
> 
> I don't find above "ssp2 playback" and "ssp2 Capture" stream names
> from sound/soc/intel/sst-mfld-platform-pcm.c so I guess it has been
> evolved a bit from those original Android drivers.
The upstream code is subset of one in Android but base stuff is still the
same

> 
> Which makes me thinking how does those strings describe the SSP port
> setup? E.g. do they reflect what port is actually used or could it
> be possible that those are just driver strings but firmware could
> have been tuned for SSP0? If I looked at earlier right, Teclast has
> the low pin-count Baytrail without SSP2 but I'm not sure about that.
The FW doesnt provide way to changes ports from driver in this, so this
doesnt mean much. If we are sure it is not ssp2, I can provide ssp1 fw for
test
> 
> >JFTR I am running a 64bit kernel, is this OK on BayTrail?
> >I guess it is, but I just wanted to mention this to be sure.
> >
> Generally yes. I've used both 32- and 64-bit kernels when developing
> the sound/soc/intel/sst-baytrail-* but I haven't tested
> sound/soc/intel/sst/. Vinod, I guess that should be 64-bit safe too?
Yup tested on both :)

-- 
~Vinod