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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <531D094C.1090205@gmail.com>
Date:	Mon, 10 Mar 2014 01:37:32 +0100
From:	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
To:	David Miller <davem@...emloft.net>
CC:	rob@...dley.net, andrew@...n.ch, f.fainelli@...il.com,
	netdev@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] net: phy: Add sysfs attribute to prevent PHY suspend

On 03/10/2014 01:30 AM, David Miller wrote:
> From: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
> Date: Mon, 10 Mar 2014 00:25:24 +0100
>
>> There is no way to determine if a bootloader is broken or not. The
>> sysfs knob allows to provide a use case based decision. Of course,
>> we can invent some freaky device tree property but that the DT
>> maintainers will not like either.
>
> My point is that whatever mechanism is used to "decide" that the sysfs
> knob gets set, can also be used to "decide" that a DT property is
> instantiated in the device tree.

The mechanism is manual, no automatic way to determine it. I understand
your point, but DT maintainers will argue here that DT is to describe HW
not SW. And a badly written bootloader initialization routine for a PHY
is SW.

Also, this will force us to maintain two sets of DT files for each
affected board: one for those with broken bootloader and one for those
with an updated, fixed bootloader. And of course, the broken bootloaders
are from pre-DT times and cannot even set that property but require the
user to pick the right DT.

If you are still against a sysfs knob, I see no way to provide a user
accessible way to prevent the PHY to be suspended. And the user is the
only reliable instance to decide not to suspend it.

Sebastian

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/