linux-kernel - Re: [PATCH 2/2] ideapad-laptop: Handle the App-controlled RF event

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Message-ID: <BANLkTimXyoC74XhZSG7jOngYdrx7yZ7nDg@mail.gmail.com>
Date:	Thu, 30 Jun 2011 11:34:55 +0100
From:	Keng-Yü Lin <kengyu@...onical.com>
To:	Ike Panhc <ike.pan@...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 2/2] ideapad-laptop: Handle the App-controlled RF event

On Wed, Jun 29, 2011 at 2:56 PM, Ike Panhc <ike.pan@...onical.com> wrote:
> On 06/28/2011 09:35 PM, Keng-Yu Lin wrote:
>> Notification with VPC2 bit 5 set is generated when the wireless
>> hotkey is pressed. BIOS fires this to notify a Windows
>> application to handle the RF switch.
>>
>> On Linux, there is no such application. This patch implements
>> a toggle for all RF devices through accessing the EC I/O ports.
>>
>> Without the explicit EC commands, the wifi LED is always on.
>>
>> Signed-off-by: Keng-Yu Lin <kengyu@...onical.com>
>> ---
>>  drivers/platform/x86/ideapad-laptop.c |    6 +++++-
>>  1 files changed, 5 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/platform/x86/ideapad-laptop.c b/drivers/platform/x86/ideapad-laptop.c
>> index 820f013..5e1e971 100644
>> --- a/drivers/platform/x86/ideapad-laptop.c
>> +++ b/drivers/platform/x86/ideapad-laptop.c
>> @@ -461,7 +461,11 @@ static void ideapad_acpi_notify(struct acpi_device *adevice, u32 event)
>>               if (test_bit(vpc_bit, &vpc1)) {
>>                       if (vpc_bit == 9)
>>                               ideapad_sync_rfk_state(adevice);
>> -                     else if (vpc_bit == 4)
>> +                     else if (vpc_bit == 13) {
>> +                             read_ec_data(handle, 0x23, &vpc2);
>> +                             write_ec_cmd(handle, 0x24, !vpc2);
>> +                             ideapad_sync_rfk_state(adevice);
>> +                     } else if (vpc_bit == 4)
>>                               read_ec_data(handle, 0x12, &vpc2);
>>                       else if (vpc_bit == 1) {
>>                       } else
>
> I think its better to implement the changes in ideapad_sync_rfk_state() because we have
> read switch status there. It is not necessary to read the same data twice in an event.
>
>

Current ideapad_sync_rfk_state() code does not really toggle the
hardware swtich (I mean to write_ec_cmd with 0x24 command). It just
assumes that the BIOS or EC is responsible for the wifi switch-on/-off
and reports the state via rfkill_set_hw_state().

In my case, without explicit sending the 0x24 command to turn off the
radio device, the wifi LED is always on.

Though it might not be true or applicable on ideapads,  in my last
experience on Dell laptops that to switch off the RF radio in the
driver while the hardware claims to control it can cause some mess-up.

So to be safe I prefer not to move the toggle code in ideapad_sync_rfk_state().

  Thanks,
-kengyu
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