linux-kernel - Re: [PATCH] Correct type and description of CONFIG_AC97_POWER_SAVE

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Date:	Sat, 07 Jun 2008 19:48:16 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Thadeu Lima de Souza Cascardo <cascardo@...aslivre.org>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Correct type and description of	CONFIG_AC97_POWER_SAVE_DEFAULT

At Sat, 7 Jun 2008 13:22:39 -0300,
Thadeu Lima de Souza Cascardo wrote:
> 
> While CONFIG_HDA_POWER_SAVE_DEFAULT is used as a timeout in seconds,
> CONFIG_AC97_POWER_SAVE_DEFAULT simply enables or disables AC97 power
> saving.

Thanks for the patch.  However, I can't take this as is.  The reasons
are below:

The power_save option takes indeed an integer value, and this kconfig
is nothing but its default value.

In your way, it's set always 1 if selected.  This is a very bad choice
as power_save value, because you'll turn on/off after one second.
This may lead to too frequent click noises. 
Thus, even if we need to make it bool, a more sensitive value must be
chosen.  And, which value is sensitive is a matter of taste, and you
cannot define it alone by yourself.


thanks,

Takashi

> ---
>  sound/pci/Kconfig           |    6 +++---
>  sound/pci/ac97/ac97_codec.c |    6 +++++-
>  2 files changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/sound/pci/Kconfig b/sound/pci/Kconfig
> index 7e47421..fe6aad2 100644
> --- a/sound/pci/Kconfig
> +++ b/sound/pci/Kconfig
> @@ -968,11 +968,11 @@ config SND_AC97_POWER_SAVE
>  	  sysfs, too.
>  
>  config SND_AC97_POWER_SAVE_DEFAULT
> -	int "Default time-out for AC97 power-save mode"
> +	bool "Activate AC97 power-save mode by default"
>  	depends on SND_AC97_POWER_SAVE
>  	default 0
>  	help
> -	  The default time-out value in seconds for AC97 automatic
> -	  power-save mode.  0 means to disable the power-save mode.
> +    By default, AC97 power-save mode is not active. This option
> +    activates it by default.
>  
>  endmenu
> diff --git a/sound/pci/ac97/ac97_codec.c b/sound/pci/ac97/ac97_codec.c
> index 45fd290..0566e3a 100644
> --- a/sound/pci/ac97/ac97_codec.c
> +++ b/sound/pci/ac97/ac97_codec.c
> @@ -48,7 +48,11 @@ module_param(enable_loopback, bool, 0444);
>  MODULE_PARM_DESC(enable_loopback, "Enable AC97 ADC/DAC Loopback Control");
>  
>  #ifdef CONFIG_SND_AC97_POWER_SAVE
> -static int power_save = CONFIG_SND_AC97_POWER_SAVE_DEFAULT;
> +#ifdef CONFIG_SND_AC97_POWER_SAVE_DEFAULT
> +static int power_save = 1;
> +#else
> +static int power_save = 0;
> +#endif
>  module_param(power_save, bool, 0644);
>  MODULE_PARM_DESC(power_save, "Enable AC97 power-saving control");
>  #endif
> -- 
> 1.5.5.3
> 
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