Re: [PATCH] ASoC: core: Change device numbering

["Amadeusz Sławiński" <amadeuszx.slawinski@linux.intel.com>]

On 1/27/2025 3:44 PM, Amadeusz Sławiński wrote:
> Currently ASoC cards when enumerating create CPUs rtds first and CODECs
> rtds second. This causes device number on cards to not start from 0, but
> from number of present CPUs. During that it does count number of rtds
> and uses it as device number visible in userspace.
> 
> This patch changes device visible to userspace, when listing cards:
> 
> Before:
> card 0: hdaudioB0D0 [hdaudioB0D0], device 1: HDAudio Analog (*) []
> card 1: hdaudioB0D2 [hdaudioB0D2], device 1: HDMI1 (*) []
> card 1: hdaudioB0D2 [hdaudioB0D2], device 2: HDMI2 (*) []
> card 1: hdaudioB0D2 [hdaudioB0D2], device 3: HDMI3 (*) []
> 
> After:
> card 0: hdaudioB0D0 [hdaudioB0D0], device 0: HDAudio Analog (*) []
> card 1: hdaudioB0D2 [hdaudioB0D2], device 0: HDMI1 (*) []
> card 1: hdaudioB0D2 [hdaudioB0D2], device 1: HDMI2 (*) []
> card 1: hdaudioB0D2 [hdaudioB0D2], device 2: HDMI3 (*) []
> 
> It is done by skipping back end devices and only counting front end
> ones.
> 
> Now there are few concerns I have:
> - while rtd->id is not used much, few drivers seem to be using it as
>    index into a table, above may break this use (although
>    "include/sound/simple_card_utils.h: * the ID stored in rtd->id may not be a valid array index."
>    suggests that maybe it is a bad idea anyway, but I'm not sure how
>    generic that comment is)
> - this will break user scripts, with hardcoded device IDs
> - this will also break some UCMs with hardcoded IDs
> 
> Now my main question is, if such patch would even be considered?
> Perhaps device IDs are not considered as "stable" interface and can be
> changed and my above worries are unnecessary.
> 
> Patch is a result of discussion from:
> https://github.com/alsa-project/alsa-ucm-conf/pull/499
> and as such I may consider others ways of fixing the problem.

And it should've been RFC in topic... :( Sorry about that.