[alsa-devel] [PATCH 0/4] ALSA: hda beep clean up
perex at perex.cz
Wed Jul 4 09:43:23 CEST 2012
Date 4.7.2012 07:16, Takashi Iwai wrote:
> 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:
>>>> 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?
>> 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
OK, thanks for the clarification. The question is, if it's the desired
behaviour. Multiple outs can cause some harmonic effects. It would be
nice, if the input layer can turn on/off (filter) the beep events at
runtime separately for all registered drivers. The setup can be handled
using sysfs or so..
Jaroslav Kysela <perex at perex.cz>
Linux Kernel Sound Maintainer
ALSA Project; Red Hat, Inc.
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