Re: [RFC PATCH] ALSA: hda/realtek: Fix speakers on ASUS PM3406CHA

[Takashi Iwai]

On Thu, 24 Sep 2026 16:45:12 +0200,
Muhtasham Nawr al-Mahmud wrote:
> 
> The ASUS ExpertBook PM3406CHA uses an ALC256 codec with subsystem
> ID 1043:1664. On Linux boot, the internal speakers are silent even
> though playback is routed to the codec and the speaker pin is
> configured for output.
> 
> The codec starts with coefficient 0x10 set to 0x1d20. Writing 0x7f20
> to coefficient 0x10 immediately restores internal speaker output.
> 
> This was reproduced on the affected hardware from a fresh boot using
> hda-verb. Reducing a larger initialization sequence showed that this
> coefficient write alone is sufficient; no GPIO, EAPD, pin-control, or
> other coefficient changes are required. After applying the coefficient
> in userspace, speaker output also remains functional across suspend
> and resume.
> 
> Add a machine-specific HDA fixup that writes the required coefficient.
> 
> The fixup has been compile-tested, but could not be boot-tested because
> the affected hardware is no longer available.
> 
> Closes: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/2162718
> Signed-off-by: Muhtasham Nawr al-Mahmud <muhtaseem2005@xxxxxxxxx>

The code change looks OK, so I applied this now.  Thanks.


Takashi