linux-kernel - Re: [PATCH 1/2] ideapad-laptop: Ignore an unused VPC notification

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Message-ID: <4E0B360B.5050600@canonical.com>
Date:	Wed, 29 Jun 2011 22:26:19 +0800
From:	Ike Panhc <ike.pan@...onical.com>
To:	Keng-Yu Lin <kengyu@...onical.com>
CC:	Matthew Garrett <mjg@...hat.com>,
	platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org,
	vanhoof@...onical.com, kent.lin@...onical.com, sylee@...onical.com
Subject: Re: [PATCH 1/2] ideapad-laptop: Ignore an unused VPC notification

On 06/28/2011 09:35 PM, Keng-Yu Lin wrote:
> BIOS fires notifications in a constant period with VPC bit 1 set when the
> power cord is unplugged.
> 
> This event is not known yet to have any effect, but it makes the
> call to sparse_keymap_report_event() and generates many KEY_UNKNOWNs.
> 
> This causes the userspace (Gnome Power Manager in my case) unable
> to enter the idle mode. As the result there is no screensaver showing up,
> no dim backlight, etc.
> 
> Signed-off-by: Keng-Yu Lin <kengyu@...onical.com>
> ---
>  drivers/platform/x86/ideapad-laptop.c |    3 ++-
>  1 files changed, 2 insertions(+), 1 deletions(-)
> 
> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
> index bfdda33..820f013 100644
> --- a/drivers/platform/x86/ideapad-laptop.c
> +++ b/drivers/platform/x86/ideapad-laptop.c
> @@ -463,7 +463,8 @@ static void ideapad_acpi_notify(struct acpi_device *adevice, u32 event)
>  				ideapad_sync_rfk_state(adevice);
>  			else if (vpc_bit == 4)
>  				read_ec_data(handle, 0x12, &vpc2);
> -			else
> +			else if (vpc_bit == 1) {
> +			} else
>  				ideapad_input_report(priv, vpc_bit);
>  		}
>  	}

So far I know this event (coming with vpc_bit=1) is for Lenovo PM utility
on Windows. For most of the machine this event is not implemented in BIOS.

Its ok that we just ignore the event.

I think it will be better if we can let sparse-keymap or any upper level
application to ignore all unknown scancode or KEY_UNKNOWN but so far I do
not know a better way then this patch.

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