Re: [PATCH v5 1/4] ACPI: NHLT: Reintroduce types the table consists of

[Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>]

On 3/4/24 13:49, Andy Shevchenko wrote:
> On Mon, Mar 04, 2024 at 10:57:39AM -0600, Pierre-Louis Bossart wrote:
>>> +/* Values for link_type field above */
>>> +
>>> +#define ACPI_NHLT_LINKTYPE_HDA			0
>>> +#define ACPI_NHLT_LINKTYPE_DSP			1
>>> +#define ACPI_NHLT_LINKTYPE_PDM			2
>>> +#define ACPI_NHLT_LINKTYPE_SSP			3
>>> +#define ACPI_NHLT_LINKTYPE_SLIMBUS		4
>>> +#define ACPI_NHLT_LINKTYPE_SDW			5
>>> +#define ACPI_NHLT_LINKTYPE_UAOL			6
>>
>> More than half of those values are not used. Is there really any benefit
>> in exposing them?
> 
> Sometimes a code is the (only) documentation. Since it's a global header and
> part of ACPICA we probably better to expose all bits that are defined.

NHLT is an Intel-only solution - no other company uses it.
Intel does not have any designs where SlimBus is productized.

I fail to see the wisdom of exposing a non-existent option with
LINKTYPE_SLIMBUS. It's not because this case was listed in a document
that we have to add the information verbatim in a open-source header.

Likewise for SoundWire we do NOT use NHLT at all...

Options 4 and 5 are completely irrelevant. 0 and 1 most likely as well.