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Date: Fri, 15 Dec 2023 02:54:20 +0000
From: Daniel Golle <daniel@makrotopia.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Andrew Lunn <andrew@lunn.ch>, Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <linux@armlinux.org.uk>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH net] net: phy: skip LED triggers on PHYs on SFP modules
Message-ID: <ZXu_3OnSzmLq5GAH@makrotopia.org>
References: <102a9dce38bdf00215735d04cd4704458273ad9c.1702339354.git.daniel@makrotopia.org>
 <20231214183123.0f0af377@kernel.org>
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In-Reply-To: <20231214183123.0f0af377@kernel.org>

On Thu, Dec 14, 2023 at 06:31:23PM -0800, Jakub Kicinski wrote:
> On Tue, 12 Dec 2023 00:05:35 +0000 Daniel Golle wrote:
> > Calling led_trigger_register() when attaching a PHY located on an SFP
> > module potentially (and practically) leads into a deadlock.
> > Fix this by not calling led_trigger_register() for PHYs localted on SFP
> > modules as such modules actually never got any LEDs.
> 
> Any suggestion of a Fixes tag?
> Looks like the triggers were added a while back, are we only seeing it
> now because we started exercising the code more?

I've noticed this as a consequence of commit 2f3ce7a56
"net: sfp: rework the RollBall PHY waiting code"
because (?) some PHYs on SFP+ now probe immediately as the previously
enforced minimum delay now became a timeout.

Blaming that commit would be wrong though, it's more that the problem
has probably always been there and was just previously augmented by
the delay.