Re: [PATCH] net: phy: Add sysfs attribute to prevent PHY suspend

From: Sebastian Hesselbarth
Date: Sun Mar 09 2014 - 20:53:51 EST


On 03/10/2014 01:41 AM, David Miller wrote:
From: Sebastian Hesselbarth <sebastian.hesselbarth@xxxxxxxxx>
Date: Mon, 10 Mar 2014 01:37:32 +0100

The mechanism is manual, no automatic way to determine it.

We recognize BIOS and ACPI bugs and work around them, by looking at
version information and whatnot, so you really can't convince me that
something similar can't be done here perhaps in the platform code.

Hmm, if the is a way to determine the version of that particual u-boot
I'd be happy to exploit that information. But I honestly doubt that.
Compared to u-boot bootloader and kernel interaction, BIOS and ACPI
are well-defined protocols.

I personally, would prefer everybody should update his broken
bootloaders, but that will just not happen.

Anyway, at least for the two boards in question, we know a bootloader
workaround. The version does support user commands to re-enable the PHY
by writing the corresponding registers.

Unfortunately, the is a bug in phy_ethtool_get_wol that up to now,
prevents most PHYs (without .wol callbacks) from being suspended.
I wanted to get in a way to disable suspend before sending a fix.

If you are that against a sysfs knob, I guess, we will just see how
many more bootloaders are broken and some will not have a way to write
PHY registers.

Sebastian
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