linux-kernel - Re: [PATCH 2/2] hp-wmi: remove GPS rfkill support via pre-2009 interface

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Message-ID: <20160308131131.GD31742@dvhart-mobl5.amr.corp.intel.com>
Date:	Tue, 8 Mar 2016 05:11:31 -0800
From:	Darren Hart <dvhart@...radead.org>
To:	"Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
Cc:	platform-driver-x86@...r.kernel.org,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Trepák Vilmos <trepo@...comga.sk>
Subject: Re: [PATCH 2/2] hp-wmi: remove GPS rfkill support via pre-2009
 interface

On Sun, Mar 06, 2016 at 11:40:19PM +0100, Maciej S. Szmigiero wrote:
> GPS rfkill support via pre-2009 WMI interface uses
> hp_wmi_get_sw_state() and hp_wmi_get_hw_state()
> to query its current hard and soft block state,
> respectively.
> 
> In hp_wmi_get_sw_state() a mask is calculated which
> bit should be checked in an int value returned by
> firmware to get current block state:
> 0x200 << (r * 8) which with r being 3 for GPS
> results in overflow and mask of zero.
> The same goes for hp_wmi_get_hw_state().
> 
> This effectively means that GPS rfkill on this
> WMI interface is considered always both hard and
> soft blocked.
> 
> Unfortunately, later when rfkill subsystem calls
> hp_wmi_set_block() to sync this block to hardware
> firmware at least on my old nc6400 gets confused
> and sets both hard and soft blocks on WiFi and BT.
> 
> This happens for example on hp-wmi module load.
> 
> Since due to overflow described above it is dubious that
> this ever worked correctly and HP laptops with modems
> having GPS support seem to all have been released well past
> year 2009 let's just remove GPS rfkill support via
> pre-2009 WMI interface.
> 

This looks reasonable. As it fails to apply without patch 1/2, please resubmit
along with my feedback for 1/2.

Also, please update your line wrap to 75 characters for commit messages.
(see Documentation/SubmittingPatches "14) The canonical patch format").

Thanks,
-- 
Darren Hart
Intel Open Source Technology Center