[alsa-devel] PATCH[1/1] Add I2S common driver for Intel MID platform

pl bossart bossart.nospam at gmail.com
Wed Oct 20 00:48:23 CEST 2010

>>         As this is used to transfer speech frames from/to cellular modem that have specific timing constraints (and modem also uses the I2S path to send some side-info), the Alsa SoC interface cannot be used.
> What makes you say this?  You have provided no detail on what problems
> you believe exist and since ASoC is a *very* thin wrapper around the
> core ALSA for DMA stuff it is very surprising that you would see any
> issues here that don't also affect plain ALSA.  If there are any issues
> then it would seem better to resolve these within the current framework
> rather than completely discarding the entire existing infrastructure.

Louis meant ALSA rather than ASOC. We use burst transfers to reduce
round-trip delay, the whole notion of periods/period elapsed/ring
buffer doesn't make sense here and there is in-band signalling that
should not be interpreted as samples. If ALSA had a simplified API for
byte streams sent over a serial output, we would have no problems
using it and of course ASOC would be used then.

>> +enum mrst_ssp_mode {
>> +       SSP_IN_NORMAL_MODE = 0x0,
>> +};
> A lot of this stuff looks suspicously like the SSP ports in Marvell CPUs
> (which were obviously Intel originally).

If it ain't broke don't fix it. :-)


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