sony-laptop: fix SNC buffer calls when SN06 returns Integers

sony-laptop: fix SNC buffer calls when SN06 returns Integers

[Zhang Rui]

Hi, Mattia,

I saw your fix for the SN06 Integer return value issue at
http://www.spinics.net/lists/platform-driver-x86/msg03934.html

here is a duplicate bug report at
https://bugzilla.kernel.org/show_bug.cgi?id=50111

I generated a similar patch as yours but I still have one concern about the fix.

memcpy(buffer, (void *)&object->integer.value, len) may break the byte order but
sony_nc_rfkill_setup() terminates if byte 0xff is checked.
is this true? or am I thinking wrong?

thanks,
rui

Re: sony-laptop: fix SNC buffer calls when SN06 returns Integers

[Mattia Dongili]

On Tue, Dec 18, 2012 at 03:08:44PM +0800, Zhang Rui wrote:
> Hi, Mattia,

Hi Rui!

> I generated a similar patch as yours but I still have one concern about the fix.

thanks for taking care of that.

> memcpy(buffer, (void *)&object->integer.value, len) may break the byte order but
> sony_nc_rfkill_setup() terminates if byte 0xff is checked.
> is this true? or am I thinking wrong?

You're correct, sony_nc_rfkill_setup() stops looking at the buffer as
soon as it hits 0xff but why do you think memcpy would break the byte
order?

-- 
mattia
:wq!

Re: sony-laptop: fix SNC buffer calls when SN06 returns Integers

[Zhang Rui]

On Wed, 2012-12-19 at 06:39 +0900, Mattia Dongili wrote:
> On Tue, Dec 18, 2012 at 03:08:44PM +0800, Zhang Rui wrote:
> > Hi, Mattia,
> 
> Hi Rui!
> 
> > I generated a similar patch as yours but I still have one concern about the fix.
> 
> thanks for taking care of that.
> 
> > memcpy(buffer, (void *)&object->integer.value, len) may break the byte order but
> > sony_nc_rfkill_setup() terminates if byte 0xff is checked.
> > is this true? or am I thinking wrong?
> 
> You're correct, sony_nc_rfkill_setup() stops looking at the buffer as
> soon as it hits 0xff but why do you think memcpy would break the byte
> order?
> 
I'm not sure how SN06 works.
say, you have supported codes 0x00, 0x10, and 0x20, what would SN06
return?
0x001020FF00000000 or 0x00000000FF201000?

thanks,
rui

Re: sony-laptop: fix SNC buffer calls when SN06 returns Integers

[Mattia Dongili]

On Wed, Dec 19, 2012 at 09:00:34AM +0800, Zhang Rui wrote:
> On Wed, 2012-12-19 at 06:39 +0900, Mattia Dongili wrote:
> > On Tue, Dec 18, 2012 at 03:08:44PM +0800, Zhang Rui wrote:
> > > Hi, Mattia,
> > 
> > Hi Rui!
> > 
> > > I generated a similar patch as yours but I still have one concern about the fix.
> > 
> > thanks for taking care of that.
> > 
> > > memcpy(buffer, (void *)&object->integer.value, len) may break the byte order but
> > > sony_nc_rfkill_setup() terminates if byte 0xff is checked.
> > > is this true? or am I thinking wrong?
> > 
> > You're correct, sony_nc_rfkill_setup() stops looking at the buffer as
> > soon as it hits 0xff but why do you think memcpy would break the byte
> > order?
> > 
> I'm not sure how SN06 works.
> say, you have supported codes 0x00, 0x10, and 0x20, what would SN06
> return?
> 0x001020FF00000000 or 0x00000000FF201000?

The return buffer is filled in sequentially and we go through it in the
same way in sony_nc_rfkill_setup(), it should be safe but here's an
example:

    Name (BUFF, Buffer (0x0410) {})                                                                              
    CreateDWordField (BUFF, Zero, BUFS)                                                                          
...

    Store (Zero, Local3)                                                                                 
    If (WLAP)                                                                                            
    {                                                                                                    
	Store (Zero, Index (BUFF, Local3))                                                               
	Add (Local3, One, Local3)                                                                        
    }                                                                                                    
													 
    If (BLTH)                                                                                            
    {                                                                                                    
	Store (0x10, Index (BUFF, Local3))                                                               
	Add (Local3, One, Local3)                                                                        
    }                                                                                                    
													 
    If (WNED)                                                                                            
    {                                                                                                    
	Store (0x20, Index (BUFF, Local3))                                                               
	Add (Local3, One, Local3)                                                                        
    }                                                                                                    

Then based on some odd consideration the method may return BUFF or BUFS
and that's where we have to take either integer.value or buffer.pointer.

Thanks!!
-- 
mattia
:wq!