alsa-ucm-conf

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The CardLongName may be derived from various DMI properties of the system, that have little to do with the card itself. Sometimes, that may be a good thing, but sometimes, it may contain the completely generic "Unknown-UnknownProduct-", see https://gitlab.com/postmarketOS/pmaports/-/issues/1498#note_1716959721 for example. At least for devices using device tree and simple-card, the name of the card (CardName), which then comes from the device tree, which can be provided by the kernel too, may be a lot more relevant, and does actually identify the device.

Why the simple-card driver does not set the CardLongName (GUI string) from DT, too? The DMI fallback for card's long name is there just for ASoC laziness.

EDIT: Also, UCM has other way to fetch the DMI info (${sys:SYSFS_PATH} substitution).

I don't think the simple-card driver can set the CardLongName from the DT right now. It would have to set long_name in struct snd_soc_card, but I couldn't find any reference to long_name in sound/soc/generic/simple-card.c. I think that would have to be added to the simple_parse_of function in that file, it seams name is set there.

Shall I send a patch for that?

If you look to conf.d/simple-card there is rockchip,es8316-codec.conf link. No idea, how this does work. It seems like that the long name is used for this match or things are really wrong. The simple-card driver should allow to modify the long name, too.

Another option is to create conf.d/simple-card/simple-card.conf and use UCM configuration for the more precise matching (${CardName} substitution and condition). Look to conf.d/USB-Audio/USB-Audio.conf for an example or conf.d/acp5x/Valve-Jupiter-1.conf (DMI matching) etc.

I think rockchip,es8316-codec.conf is used by the pinebook-pro. In it's dtb, on line 133 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/boot/dts/rockchip/rk3399-pinebook-pro.dts#n133 it says simple-audio-card,name = "rockchip,es8316-codec";. That only sets the name, not the long name, though.

So, the circumstances in which this works are probably going to be about the same as for the pinephone-pro. For distros where the kernel is loaded directly by uboot without EFI, there will be no DMI, and the long_name is going to fall back to name, here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/sound/soc/soc-core.c?id=052d534373b7ed33712a63d5e17b2b6cdbce84fd#n2268 (line 2268).

It seams there is also a blacklist of invalid DMI names in the kernel, I'll add Unknown and Unknown Product to that list.

I will also look into doing the matching in conf.d/simple-card/simple-card.conf, and will update this pull request later once I've figured that out.