Re: [PATCH] ALSA: hda/tas2781: Only accept CRC-less V1 data if all entries are valid

[Gergo Koteles]

Hi Mohamed,

On Tue, 2026-11-03 at 10:27 +0100, Mohamed Yassine Jebabli via B4 Relay
wrote:
> From: Mohamed Yassine Jebabli <med.jebabli@xxxxxxxxx>
> 
> Commit 408249089c48 ("ALSA: hda/tas2781: Accept V1 calibration data
> without CRC") only checked the first device entry. On machines where
> the BIOS populates fewer entries than p->ndev, the remaining all-zero
> entries are applied and tas2781_cali_preproc() divides by zero on
> playback open.
> 
> Accept CRC-less V1 data only if every expected entry is non-zero and
> self-consistent (R0 * 1/R0 close to 1.0), otherwise reject it as
> before.
> 

...

>  
> +/*
> + * V1 data without CRC is only trusted if every expected device has a
> + * populated, self-consistent entry: R0 (Q27) * 1/R0 (Q31) must be
> + * close to 1.0 in Q58.
> + */

Just out of curiosity, where do Q27, Q31, Q58 come from?
I couldn't find anything about these.

Thanks,
Gergo