Wireless interface power

John Watlington wad at laptop.org
Fri Apr 20 06:37:25 EDT 2007

"All problems are related"   -Mitch

    In debugging a suspend problem on B3, we ran across the cause of the
problem you indicated.   We will add it to the list of ECRs required  
to debug
suspend/resume on a B2 when we have a verified fix.

When we tried to verify the problem earlier, we discovered an  
inability to
successfully suspend/resume.   Our voltage readings at that time were
erroneous.   Tests on a unit which successfully suspends/resumes  
that WLAN_3.3V is pulled down through a design error (the switches  
it aren't completely turned off!)


On Apr 19, 2007, at 10:26 PM, Javier Cardona wrote:

> Forwarded to the list.  Maybe someone else has an answer for this:
> ---------- Forwarded message ----------
> From: Andrey Yurovsky <andrey at cozybit.com>
> Date: Apr 18, 2007 9:33 PM
> Subject: Re: msh0 interface behavior change proposal
> To: John Watlington <wad at laptop.org>, Javier Cardona  
> <javier at cozybit.com>
> Hi John.  We tried suspending to RAM with the suspend6 (I think) and
> stock firmwares on build 384 and power was definitely cut:
> 1) attached debugger to WLAN module
> 2) # echo m > /sys/power/state
> 3) system suspends, [JTAG] debugger is no longer attached to the WLAN
> module's processor
> I checked /sys/power/state and it has 'mem' and 'disk' options, so I
> assume 'mem' is right.  Is there something I'm doing wrong or is there
> some other way to have it suspend but keep the power to the WLAN
> module on?  Thanks,
>   -Andrey
> On 4/18/07, John Watlington <wad at laptop.org> wrote:
>> Javier,
>>     Power to the WLAN is NOT cut during suspend.  My explanation of
>> power domains
>> needs clarification.   The WLAN is powered almost continuously
>> (possibly even when
>> the laptop is powered off).   Hence it is in the "green" domain, not
>> the yellow domain.
>> (...)
>> wad
>> On Apr 18, 2007, at 10:07 PM, Javier Cardona wrote:
>>> All,
>>> (...)
>>> PS.  Unfortunately the wlan power is cut off when the laptop is
>>> suspended.  Otherwise we we would have basic autonomous mode up and
>>> running by now (
>>> http://wiki.laptop.org/go/
>>> Hardware_Power_Domains#Powered_in_Suspend_.28Yellow.29
>>> ).
> _______________________________________________
> Devel mailing list
> Devel at laptop.org
> http://mailman.laptop.org/mailman/listinfo/devel

More information about the Devel mailing list