[alsa-devel] [PATCH 0/4] ALSA: hda beep clean up

[Takashi Iwai]

At Tue, 03 Jul 2012 22:01:45 +0200,
Jaroslav Kysela wrote:
> 
> Date 3.7.2012 18:31, Jaroslav Kysela wrote:
> > Date 3.7.2012 18:03, Takashi Iwai wrote:
> >> Hi,
> >>
> >> this is a series of small cleanups of HD-audio beep code.
> >> Since the keyboard driver already handles the simultaneous outputs
> >> from the multiple input beep instances, there is no merit to have
> >> beep_mode=2 option to switch the beep input device.
> > 
> > Acked-by: Jaroslav Kysela <perex at perex.cz>
> 
> While I acked this, I vaguely remember now, that the event duplication
> (simultaneous outputs) caused some issues on some Lenovo notebooks.
> 
> When the pcspkr and HDA beep generator is connected to the same output
> (integrated speakers), it may cause some issues (bad beep quality -
> frequency etc.).
> 
> I looked to the input code, and the kd_mksound() calls
> input_handler_for_each_handle(), thus the event is duplicated to all
> beep generators, right?

Right.

> The beep_mode=2 was introduced to let users to help with this issue with
> a comfortable way.

Not really.  At the time this was introduced, the keyboard driver took
only a single input handle exclusively, namely only the last
registered one.  Thus playing on both had never happened until
recently.


Takashi