On 12/17/2013 08:43 PM, David Miller wrote:
> From: Sebastian Hesselbarth <[email protected]>
> Date: Fri, 13 Dec 2013 10:20:24 +0100
>
>> This is v2 of the ethernet PHY power optimization patches to reduce
>> power consumption of network PHYs with link that are either unused or
>> the corresponding netdev is down.
>>
>> Compared to the last version, this patch set drops a patch to disable
>> unused PHYs after late initcall, as it is not compatible with a modular
>> mdio bus [1]. I'll investigate different ways to have a modular mdio bus
>> driver get notified when driver loading is done.
>>
>> Again, a branch with v2 applied to v3.13-rc2 can also be found at
>> https://github.com/shesselba/linux-dove.git topic/ethphy-power-v2
>>
>> [1] http://www.spinics.net/lists/arm-kernel/msg293028.html
>
> Series applied, thanks.
>
David, Mungunthan, Florian,
as expected the above patches create a Linux to bootloader dependency
that surfaces dumb bootloaders not initializing PHYs correctly.
Andrew has a Kirkwood based board that does not power-up and restart
auto-negotiation on the powered down PHY after a warm restart. While
this specific bootloader allows a soft-workaround by issuing the
required PHY writes before accessing the interface, others may not.
I think we should allow the user to soft-disable the automatic
power-down of PHYs, i.e. by exploiting a kernel parameter.
Do you have any preference for naming it? My call would be something
like libphy.suspend_halted = [0,1] with 1 being the default.
Sebastian
Hi Sebastian,
2014-02-04 Sebastian Hesselbarth <[email protected]>:
> On 12/17/2013 08:43 PM, David Miller wrote:
>>
>> From: Sebastian Hesselbarth <[email protected]>
>> Date: Fri, 13 Dec 2013 10:20:24 +0100
>>
>>> This is v2 of the ethernet PHY power optimization patches to reduce
>>> power consumption of network PHYs with link that are either unused or
>>> the corresponding netdev is down.
>>>
>>> Compared to the last version, this patch set drops a patch to disable
>>> unused PHYs after late initcall, as it is not compatible with a modular
>>> mdio bus [1]. I'll investigate different ways to have a modular mdio bus
>>> driver get notified when driver loading is done.
>>>
>>> Again, a branch with v2 applied to v3.13-rc2 can also be found at
>>> https://github.com/shesselba/linux-dove.git topic/ethphy-power-v2
>>>
>>> [1] http://www.spinics.net/lists/arm-kernel/msg293028.html
>>
>>
>> Series applied, thanks.
>>
>
> David, Mungunthan, Florian,
>
> as expected the above patches create a Linux to bootloader dependency
> that surfaces dumb bootloaders not initializing PHYs correctly.
>
> Andrew has a Kirkwood based board that does not power-up and restart
> auto-negotiation on the powered down PHY after a warm restart. While
> this specific bootloader allows a soft-workaround by issuing the
> required PHY writes before accessing the interface, others may not.
>
> I think we should allow the user to soft-disable the automatic
> power-down of PHYs, i.e. by exploiting a kernel parameter.
>
> Do you have any preference for naming it? My call would be something
> like libphy.suspend_halted = [0,1] with 1 being the default.
The name looks good to me, and it would avoid having to clear the
BMCR_PWRDOWN bit during the MDIO bus remove callback to workaround
such bootloaders.
BTW, it looks like we are omitting a 0.5 seconds delay after clearing
the BMCR_PWRDOWN bit:
"
22.2.4.1.5 Power Down
...
A PHY is not required to meet the RX_CLK and TX_CLK signal functional
requirements when either bit
0.11 or bit 0.10 is set to a logic one. A PHY shall meet the RX_CLK
and TX_CLK signal functional require-
ments defined in 22.2.2 within 0.5 s after both bit 0.11 and 0.10 are
cleared to zero."
--
Florian
Hi Sebastian,
On Tue, Feb 04, 2014 at 08:38:22PM +0100, Sebastian Hesselbarth wrote:
> On 12/17/2013 08:43 PM, David Miller wrote:
> > From: Sebastian Hesselbarth <[email protected]>
> > Date: Fri, 13 Dec 2013 10:20:24 +0100
> >
> >> This is v2 of the ethernet PHY power optimization patches to reduce
> >> power consumption of network PHYs with link that are either unused or
> >> the corresponding netdev is down.
> >>
> >> Compared to the last version, this patch set drops a patch to disable
> >> unused PHYs after late initcall, as it is not compatible with a modular
> >> mdio bus [1]. I'll investigate different ways to have a modular mdio bus
> >> driver get notified when driver loading is done.
> >>
> >> Again, a branch with v2 applied to v3.13-rc2 can also be found at
> >> https://github.com/shesselba/linux-dove.git topic/ethphy-power-v2
> >>
> >> [1] http://www.spinics.net/lists/arm-kernel/msg293028.html
> >
> > Series applied, thanks.
> >
[..]
>
> as expected the above patches create a Linux to bootloader dependency
> that surfaces dumb bootloaders not initializing PHYs correctly.
>
> Andrew has a Kirkwood based board that does not power-up and restart
> auto-negotiation on the powered down PHY after a warm restart. While
> this specific bootloader allows a soft-workaround by issuing the
> required PHY writes before accessing the interface, others may not.
>
I'm also having this same issue on Kirkwood USI Topkick, running
v3.14-rc1.
--
Ezequiel García, Free Electrons
Embedded Linux, Kernel and Android Engineering
http://free-electrons.com