Re: [Bug 106031] Regression in 4.2.x: in airplane mode each time I open my laptop lid

[Darren Hart <dvhart@infradead.org>]

On Thu, Oct 22, 2015 at 12:54:33PM +0200, Gabriele Mazzotta wrote:
> On 22/10/2015 12:50, Pali Rohár wrote:
> >On Thursday 22 October 2015 12:44:08 Gabriele Mazzotta wrote:
> >>On 22/10/2015 10:51, Pali Rohár wrote:
> >>>On Thursday 22 October 2015 10:26:47 Gabriele Mazzotta wrote:
> >>>>I'll see if I can find a batter way to deal with this problem,
> >>>>dell-laptop can detect the presence of an hardware switch.
> >>>
> >>>dell-rbtn.ko has acpi method CRBT which returns if notebook has hw switch or
> >>>toggle key.
> >>>
> >>>And rfkill implementation in dell-laptop.ko does not work correctly on
> >>>XPS machines. And because userspace implementation of smbios works fine,
> >>>I think that problem is in kernel driver rather in BIOS/firmware...
> >>
> >>I was thinking about something such as the following, which should favor
> >>the hardware slider when available. This should work if my assumption is
> >>correct, that is the laptops with a working RBTN method are the ones
> >>having problems.
> >>
> >
> >Hm... wait! There are machines with HW slider and type is RBTN_TOGGLE?
> >
> >I thought that all machines with HW slider has type RBTN_SLIDER and
> >others have RBTN_TOGGLE.
> 
> Yes, this is the problem I've been talking about ever since the work
> on this driver started. AFAIK we don't know how to detect these laptops
> (my XPS13 is one of them).

Where is the radio hw slider on this machine?

This patch would effectively ignore Fn-F2 (radio toggle) key on this machine
then - correct? I don't think that is desirable either.

Seems to me the desired behavior would be to restore the radio state on resume.
Consider the following table:

SW: Switch state
SS: State at suspend
SR: State after resume
 0: WiFi Enabled
 1: WiFi Disabled

State SW SS SR
--------------
a      0  0  0
b      0  1  1   (switch is enabled, but toggle key disabled wifi)
c      1  0  N/A (invalid state)
d      1  1  1

State "a" is where we are failing currently I believe?

Do we know if DELRBTN and DELLABCE are always a TOGGLE or a SLIDER respectively?
I'm wondering if these should be separate drivers.

-- 
Darren Hart
Intel Open Source Technology Center