[alsa-devel] Regression: very quiet speakers on Thinkpad T570s

[Jeremy Cline]

On 12/1/18 9:44 AM, Takashi Iwai wrote:
> On Fri, 30 Nov 2018 17:51:33 +0100,
> Jeremy Cline wrote:
>>
>> On 11/30/18 11:00 AM, Takashi Iwai wrote:
>>> On Fri, 30 Nov 2018 15:49:17 +0100,
>>> Jeremy Cline wrote:
>>>>
>>>> Hi,
>>>>
>>>> Some folks have reported on the Fedora bug tracker[0] that the laptop
>>>> speaker volume is very low on the Thinkpad T570 when running a kernel
>>>> that includes commit 61fcf8ece9b6 ("ALSA: hda/realtek - Enable Thinkpad
>>>> Dock device for ALC298 platform").
>>>>
>>>> alsa-info.sh from v4.15.4 (just before commit 61fcf8ece9b6 arrived in
>>>> stable) and v4.19.4 with the issue present are attached to the bugzilla.
>>>> I've also Cc'd Tim, who uploaded them and has the laptop in question.
>>>>
>>>> [0] https://bugzilla.redhat.com/show_bug.cgi?id=1554304
>>>
>>> Could you pinpoint which kernel version started showing the
>>> regression, at least?  The diffs are fairly wide between 4.15 and
>>> 4.19.
>>
>> Ah, sorry for not being more clear. The regression appears to be
>> introduced by commit 61fcf8ece9b6, which got backported to v4.15.5
>> because it addressed a bug with the dock[0]. v4.19.4 with that commit
>> reverted works, according to the bug reporter.
>>
>> [0] https://bugzilla.kernel.org/show_bug.cgi?id=195161
> 
> OK, then this seems to be the change of DAC assignment.
> 
> Maybe the hardware has some implicit assumption of NID 0x03 bound with
> the speaker pin.  Below is a patch for fixing the pin / DAC mapping.
> Please give it a try.
> 
> 
> thanks,
> 
> Takashi
> 
> ---
> diff --git a/sound/pci/hda/patch_realtek.c b/sound/pci/hda/patch_realtek.c
> index 06f93032d0cc..50bc2e97d799 100644
> --- a/sound/pci/hda/patch_realtek.c
> +++ b/sound/pci/hda/patch_realtek.c
> @@ -4988,9 +4988,14 @@ static void alc_fixup_tpt470_dock(struct hda_codec *codec,
>  		{ 0x19, 0x21a11010 }, /* dock mic */
>  		{ }
>  	};
> +	static hda_nid_t preferred_pairs[] = {
> +		0x14, 0x03, 0x17, 0x02, 0x21, 0x02,
> +		0
> +	};
>  	struct alc_spec *spec = codec->spec;
>  
>  	if (action == HDA_FIXUP_ACT_PRE_PROBE) {
> +		spec->gen.preferred_dacs = preferred_pairs;
>  		spec->parse_flags = HDA_PINCFG_NO_HP_FIXUP;
>  		snd_hda_apply_pincfgs(codec, pincfgs);
>  	} else if (action == HDA_FIXUP_ACT_INIT) {
> 

That patch does indeed fix the problem according to the original
reporter.

Thanks,
Jeremy