[alsa-devel] writing an alsa driver

[Liam Girdwood]

On Thu, 2015-06-04 at 10:59 +0200, Michele Curti wrote:
> I'm back now from a period of limited internet access, I tried to
> change the
> irqindex_host_ipc to 0 (like the others platforms)
> 
> diff --git a/sound/soc/intel/common/sst-acpi.c
> b/sound/soc/intel/common/sst-acpi.c
> index 42f293f..7cc64e3 100644
> --- a/sound/soc/intel/common/sst-acpi.c
> +++ b/sound/soc/intel/common/sst-acpi.c
> @@ -258,7 +258,7 @@ static struct sst_acpi_desc sst_acpi_baytrail_desc
> = {
>         .resindex_lpe_base = 0,
>         .resindex_pcicfg_base = 1,
>         .resindex_fw_base = 2,
> -       .irqindex_host_ipc = 5,
> +       .irqindex_host_ipc = 0,
>         .sst_id = SST_DEV_ID_BYT,
>         .resindex_dma_base = -1,
>  };
> 
> and the sound card showed up.  So I tried to play a bit with alsamixer
> and got
> some cracking noise.
> 
> Tried to play some songs but a song of 4 minutes finished in about a
> dozen of
> seconds..  Maybe the clocks are not correctly configured..
> 
> After a while I smelt a smell of burnt components and the chassis near
> the
> speakers was hot like hell.  Shutdown the laptop.
> 
> Now I'm not sure the hardware is damaged, after a couple of hours I
> tried to
> reboot and got a (strange) beep during boot, so maybe I was lucky..
> 
> Anyway, now I removed the change.

The speakers are probably being over powered so best to make sure with
alsamixer that all the gains are low or muted and all unused
inputs/outputs are muted or off before playing any audio. You can then
gradually increase the volume to the desired level. 

Liam