[alsa-devel] [PATCH v2 1/2] ASoC: SOF: add flag for position update ipc

[Keyon Jie]

On 2019/7/4 下午6:03, Kai Vehmanen wrote:
> Hi,
> 
> patch looks good, but commit message could be improved.
> 
> On Wed, 3 Jul 2019, Keyon Jie wrote:
> 
>> In some cases, FW might need use the host_period_bytes even no position
>> update ipc reqiured from driver, here add another flag for position update,
>> and preserve host_period_bytes for FW to use.
> 
> Speculation on what FW might do is not really needed. The
> host_period_bytes field has been overloaded with multiple
> semantics and this patch clears that, right. How about:

Well, to me it is flavor choice, Ranjani suggested to illustrate the use 
case where the FW will use this host_period_bytes, and I agreed this 
will help people to understand why we need this change.

> 
> ""
> Remove the special case semantics of 'host_period_bytes==0'.
> Add a new field 'no_period_irq' to signal whether period elapsed
> IPC should be sent and use 'host_period_bytes' only for
> period size.
> ""
> 
>> This might require corresponding FW change and ABI alignment.
> 
> This is not helpful -- we know this _is_ a minor ABI change
> and needs to be aligned with FW.

It is minor change, but the FW change is still required, otherwise, we 
will get extra position update IPCs which may confuse the driver, please 
refer to here:
https://github.com/thesofproject/sof/pull/1592

Thanks,
~Keyon

> 
> Br, Kai
> 
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