Re: [PATCH v2 net-next 1/3] led: trig: netdev: Fix requesting offload device

From: Andrew Lunn <andrew@lunn.ch>
To: Daniel Golle <daniel@makrotopia.org>
Cc: netdev <netdev@vger.kernel.org>,
	Heiner Kallweit <hkallweit1@gmail.com>,
	Russell King <rmk+kernel@armlinux.org.uk>,
	Simon Horman <simon.horman@corigine.com>,
	Christian Marangi <ansuelsmth@gmail.com>
Subject: Re: [PATCH v2 net-next 1/3] led: trig: netdev: Fix requesting offload device
Date: Tue, 8 Aug 2023 01:48:46 +0200	[thread overview]
Message-ID: <912e0408-dc5a-44dc-87a1-dc1572c427d8@lunn.ch> (raw)
In-Reply-To: <ZNF0_SvsUdk8Dvta@makrotopia.org>

> So setting the brigthness should result in the trigger to be cleared
> back to 'none' then, and that would result in calling
> netdev_trig_deactivate if it was previously active.
> 
> Because otherwise, even if I take care of truning off all hardware
> triggers in the led_set_brightness call, the netdev trigger would
> still be selected.

I looked at edtrig-timer.c, which can offload the blinking to hardware
if it supports the needed op. Its deactivate function is:

static void timer_trig_deactivate(struct led_classdev *led_cdev)
{
        /* Stop blinking */
        led_set_brightness(led_cdev, LED_OFF);
}

So this does suggest the trigger should disable offload. v3 will do
similar.

	Andrew