linux-kernel - Re: [PATCH 0/8] [Resend] ideapad: using EC command to control rf/camera power

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Message-ID: <4C6BDA6E.1060300@canonical.com>
Date:	Wed, 18 Aug 2010 21:04:46 +0800
From:	Ike Panhc <ike.pan@...onical.com>
To:	David Woodhouse <dwmw2@...radead.org>
CC:	"platform-driver-x86@...r.kernel.org" 
	<platform-driver-x86@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	Thomas Renninger <trenn@...e.de>,
	Alan Cox <alan@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Corentin Chary <corentincj@...aif.net>,
	Randy Dunlap <randy.dunlap@...cle.com>,
	"Brown, Len" <len.brown@...el.com>,
	Matthew Garrett <mjg@...hat.com>
Subject: Re: [PATCH 0/8] [Resend] ideapad: using EC command to control rf/camera
 power

On 08/18/2010 06:35 PM, David Woodhouse wrote:
> On Wed, 2010-08-18 at 09:36 +0100, Ike Panhc wrote:
>>
>> Once the rfkill of a laptop is set to block, it is no way to unblock with Linux
>> without driver. Thanks for David Woodhouse wrote the first driver solving this.
>>
>> But the \_SB_.GECN and \_SB_.DECN are only available on Lenovo ideapad S10-3.
>> Using EC command to control rf/camera power is better because I believe every
>> ideapads which has VPC2004 device in its DSDT has this common method.
>>
>> This driver is tested and work fine on Lenovo ideapad B550 and ideapad S10-3.
> 
> Works for me too (on S10-3); thanks.
> 
> It all looks good, although should we have a delay or a schedule or at
> least a cpu_relax() in the read_ec_data() and write_ec_cmd() loops?
> Those loops should be using time_before() too, rather than open-coding
> the comparison.
> 
yeah, agree. polling from ec makes cpu busy, although its usually less then 10ms
a yield or relax will be good.
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