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From: Russell King - ARM Linux admin <linux@armlinux.org.uk>
To: Ben Whitten <ben.whitten@gmail.com>, Dan Murphy <dmurphy@ti.com>
Cc: linux-leds@vger.kernel.org, netdev@vger.kernel.org
Subject: leds: netdev trigger - misleading link state indication at boot
Date: Tue, 13 Apr 2021 19:20:51 +0100	[thread overview]
Message-ID: <20210413182051.GR1463@shell.armlinux.org.uk> (raw)

Hi,

I'm seeing some odd behaviour with the netdev trigger and some WiFi
interfaces.

When the WiFi interface has never been brought up (so is in an
operationally disabled state), if I bind a LED to the netdev
trigger, setting the device_name to the WiFi interface name and
enable the "link" property, the LED illuminates, indicating that
the WiFi device has link - but it's disabled.

If I up/down the WiFi interface, thereby returning it to the
original state, the link LED goes out.

I suspect ledtrig-netdev.c needs to check that the device is both
up (dev->flags & IFF_UP) and netif_carrier_ok(dev) both return true,
rather than just relying on netif_carrier_ok(). I don't think using
netif_running() is appropriate, as that will return true before
ndo_open() has been called to initialise the carrier state.

Agreed?

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

             reply	other threads:[~2021-04-13 18:21 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-13 18:20 Russell King - ARM Linux admin [this message]
2021-08-04 16:01 ` leds: netdev trigger - misleading link state indication at boot Pavel Machek

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