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From: Lukas Wunner <lukas@wunner.de>
To: Andrew Lunn <andrew@lunn.ch>
Cc: Steve Glendinning <steve.glendinning@shawell.net>,
	UNGLinuxDriver@microchip.com, Oliver Neukum <oneukum@suse.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	netdev@vger.kernel.org, linux-usb@vger.kernel.org,
	Andre Edich <andre.edich@microchip.com>,
	Oleksij Rempel <o.rempel@pengutronix.de>,
	Martyn Welch <martyn.welch@collabora.com>,
	Gabriel Hojda <ghojda@yo2urs.ro>,
	Christoph Fritz <chf.fritz@googlemail.com>,
	Lino Sanfilippo <LinoSanfilippo@gmx.de>,
	Philipp Rosenberger <p.rosenberger@kunbus.com>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>
Subject: Re: [PATCH net] usbnet: smsc95xx: Fix deadlock on runtime resume
Date: Wed, 27 Apr 2022 17:45:01 +0200	[thread overview]
Message-ID: <20220427154501.GB15329@wunner.de> (raw)
In-Reply-To: <YmlgQhauzZ/tkX/v@lunn.ch>

On Wed, Apr 27, 2022 at 05:24:50PM +0200, Andrew Lunn wrote:
> You have looked at this code, tried a few different things, so this is
> probably a dumb question.
> 
> Do you actually need to call phy_init_hw()?

I should add that the PHY register state may not be preserved on
runtime PM if woken via the ->reset_resume hook and I believe
that's the case when phy_init_hw() is necessary.

smsc95xx_suspend() currently accesses PHY registers behind the
PHY driver's back to enable Energy Detect Powerdown and it
uses smsc95xx_mdio_write_nopm() for that, hence that doesn't
deadlock *currently*, but the code should be moved to the PHY
driver, and then it will.

Thanks,

Lukas

      parent reply	other threads:[~2022-04-27 15:45 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-27  6:41 [PATCH net] usbnet: smsc95xx: Fix deadlock on runtime resume Lukas Wunner
2022-04-27 14:00 ` Alan Stern
2022-04-27 15:10   ` Lukas Wunner
2022-04-27 15:24 ` Andrew Lunn
2022-04-27 15:38   ` Lukas Wunner
2022-04-27 18:19     ` Alan Stern
2022-04-27 15:45   ` Lukas Wunner [this message]

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