power off ath0: <Atheros AR946x/AR948x>

Adrian Chadd adrian at freebsd.org
Tue Jan 13 15:57:34 UTC 2015


All atheros PCI/PCIe devices.


-a


On 13 January 2015 at 01:13, Lars Engels <lars.engels at 0x20.net> wrote:
> On Mon, Jan 12, 2015 at 11:20:07AM -0800, Adrian Chadd wrote:
>> On 12 January 2015 at 08:56, Warner Losh <imp at bsdimp.com> wrote:
>> >
>> >> On Jan 12, 2015, at 9:54 AM, John Baldwin <jhb at FreeBSD.org> wrote:
>> >>
>> >> On 1/11/15 3:05 AM, Matthias Apitz wrote:
>> >>>
>> >>> Hello,
>> >>>
>> >>> Is there a way to completely power-off the Wifi chip in my Acer C720?
>> >>> I tried 'ifconfig ath0 down' which saves around 20 mA. But the LED stays
>> >>> on, which let me think it is still someow on-air.
>> >>
>> >> Not yet.  You could try setting the tunable to disable power for PCI
>> >> devices without a driver and not include 'ath' in your kernel config.  I
>> >> will (soon) commit a new 'devctl' tool to HEAD that would let you do
>> >> 'devctl suspend ath0' to do this.
>> >
>> > I’d love to see this tied into the forthcoming work on PCIe hot plug as well,
>> > which is one way to power off the slot. But that work seems to be stalled…
>>
>> Right. So, the driver in -HEAD should be powering off almost all of
>> the chip when no vap (ie, wlanX) is active. The only parts of the chip
>> that stay on is the PCIe PHY and the GPIO/RTC block. AFAIK we don't
>> support PCIe power save state management at the moment, so we can't
>> keep the PCIe PHY off.
>>
>> But yeah, most of the chip is off. The chip doesn't take all that much
>> power unless it's actively transmitting/receiving. The LEDs are on
>> because the GPIO block is on and it's likely holding the LED up.
>
> Is that only true for this chip, all ath ones or even all wireless
> devices?


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