Re: Questions about Runtime Power Management

From: Oliver Neukum
Date: Sun Jun 16 2013 - 18:14:14 EST


On Sunday 16 June 2013 23:07:36 Ming Lei wrote:
> On Mon, Jun 10, 2013 at 12:28 AM, Morales, Alejandra
> <alejandra.morales@xxxxxx> wrote:
>
> > - Is runtime power management supported by net devices?
>
> Currently, 'struct net_device' doesn't support runtime power management,
> and I submitted one patch to add the support for solving accessing
> suspended device by 'ethtool', but it was rejected.
>
> http://marc.info/?t=135054860600003&r=1&w=2

And the discussion is still useful and true.

> But the physical device of the net device can support runtime PM, for example,
> some PCIe network devices support runtime PM on link change, and usbnet
> devices support auto suspend.

There is a design behind runtime PM. Runtime PM is involved if a device looses
capabilities in a power saving state. Or if it is a dependency among runtime PM
of devices. Therefore it is not used for things like Energy Efficient Ethernet.

Regards
Oliver

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