[PATCH v2] ALSA: hda/realtek - a fake key event is triggered by running shutup

[Takashi Iwai]

On Sun, 29 Mar 2020 10:20:18 +0200,
Hui Wang wrote:
> 
> On the Lenovo X1C7 machines, after we plug the headset, the rt_resume()
> and rt_suspend() of the codec driver will be called periodically, the
> driver can't stay in the rt_suspend state even users doen't use the
> sound card.
> 
> Through debugging, I found  when running rt_suspend(), it will call
> alc225_shutup(), in this function, it will change 3k pull down control
> by alc_update_coef_idx(codec, 0x4a, 0, 3 << 10), this will trigger a
> fake key event and that event will resume the codec, when codec
> suspend agin, it will trigger the fake key event one more time, this
> process will repeat.
> 
> If disable the key event before changing the pull down control, it
> will not trigger fake key event. It also needs to restore the pull
> down control and re-enable the key event, otherwise the system can't
> get key event when codec is in rt_suspend state.
> 
> Also move some functions ahead of alc225_shutup(), this can save the
> function declaration.
> 
> Fixes: 76f7dec08fd6 (ALSA: hda/realtek - Add Headset Button supported for ThinkPad X1)
> Cc: Kailang Yang <kailang at realtek.com>
> Cc: <stable at vger.kernel.org>
> Signed-off-by: Hui Wang <hui.wang at canonical.com>

Applied now.  Thanks.


Takashi