c2a6ffe3f1
[ Upstream commit cc941e548bffc01b5816b4edc5cb432a137a58b3 ]
Uwe reports:
"Most PHYs signal WoL using an interrupt. So disabling interrupts [at
shutdown] breaks WoL at least on PHYs covered by the marvell driver."
Discussing with Ioana, the problem which was trying to be solved was:
"The board in question is a LS1021ATSN which has two AR8031 PHYs that
share an interrupt line. In case only one of the PHYs is probed and
there are pending interrupts on the PHY#2 an IRQ storm will happen
since there is no entity to clear the interrupt from PHY#2's registers.
PHY#1's driver will get stuck in .handle_interrupt() indefinitely."
Further confirmation that "the two AR8031 PHYs are on the same MDIO
bus."
With WoL using interrupts to wake the system, in such a case, the
system will begin booting with an asserted interrupt. Thus, we need to
cope with an interrupt asserted during boot.
Solve this instead by disabling interrupts during PHY probe. This will
ensure in Ioana's situation that both PHYs of the same type sharing an
interrupt line on a common MDIO bus will have their interrupt outputs
disabled when the driver probes the device, but before we hook in any
interrupt handlers - thus avoiding the interrupt storm.
A better fix would be for platform firmware to disable the interrupting
devices at source during boot, before control is handed to the kernel.
Fixes: e2f016cf7751 ("net: phy: add a shutdown procedure")
Link: 20230804071757.383971-1-u.kleine-koenig@pengutronix.de
Reported-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.