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From: Pavel Machek <pavel@ucw.cz>
To: "Marek Behún" <kabel@kernel.org>
Cc: netdev@vger.kernel.org, linux-leds@vger.kernel.org,
	Dan Murphy <dmurphy@ti.com>, Russell King <linux@armlinux.org.uk>,
	Andrew Lunn <andrew@lunn.ch>,
	Matthias Schiffer <matthias.schiffer@ew.tq-group.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jacek Anaszewski <jacek.anaszewski@gmail.com>,
	Ben Whitten <ben.whitten@gmail.com>
Subject: Re: [PATCH RFC leds + net-next 7/7] net: phy: marvell: support LEDs connected on Marvell PHYs
Date: Wed, 25 Nov 2020 13:38:17 +0100	[thread overview]
Message-ID: <20201125123817.GI29328@amd> (raw)
In-Reply-To: <20201030114435.20169-8-kabel@kernel.org>

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> +/* FIXME: Blinking rate is shared by all LEDs on a PHY. Should we check whether
> + * another LED is currently blinking with incompatible rate? It would be cleaner
> + * if we in this case failed to offload blinking this LED.
> + * But consider this situation:
> + *   1. user sets LED[1] to blink with period 500ms for some reason. This would
> + *      start blinking LED[1] with perion 670ms here

period.

> + *   2. user sets netdev trigger to LED[0] to blink on activity, default there
> + *      is 100ms period, which would translate here to 84ms. This is
> + *      incompatible with the already blinking LED, so we fail to offload to HW,
> + *      and netdev trigger does software offloading instead.
> + *   3. user unsets blinking od LED[1], so now we theoretically can offload
> + *      netdev trigger to LED[0], but we don't know about it, and so it is left
> + *      in SW triggering until user writes the settings again
> + * This could be solved by the netdev trigger periodically trying to offload to
> + * HW if we reported that it is theoretically possible (by returning -EAGAIN
> + * instead of -EOPNOTSUPP, for example). Do we want to do this?
> + */

I believe we should check & fallback to software if there's already
incompatible rate in use. No need to periodically re-try to activate
the offload.

Best regards,
								Pavel

-- 
http://www.livejournal.com/~pavelmachek

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  reply	other threads:[~2020-11-25 12:38 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-30 11:44 [PATCH RFC leds + net-next 0/7] netdev trigger offloading and LEDs on Marvell PHYs Marek Behún
2020-10-30 11:44 ` [PATCH RFC leds + net-next 1/7] leds: trigger: netdev: don't explicitly zero kzalloced data Marek Behún
2020-11-25 12:34   ` Pavel Machek
2020-10-30 11:44 ` [PATCH RFC leds + net-next 2/7] leds: trigger: netdev: simplify the driver by using bit field members Marek Behún
2020-10-30 22:37   ` Jacek Anaszewski
2020-10-30 23:45     ` Marek Behún
2020-11-01 16:40       ` Jacek Anaszewski
2021-03-01 10:30   ` Pavel Machek
2020-10-30 11:44 ` [PATCH RFC leds + net-next 3/7] leds: trigger: add API for HW offloading of triggers Marek Behún
2021-03-01 10:38   ` Pavel Machek
2020-10-30 11:44 ` [PATCH RFC leds + net-next 4/7] leds: trigger: netdev: support HW offloading Marek Behún
2020-11-05 14:44   ` Marek Behún
2021-03-01 10:44   ` Pavel Machek
2020-10-30 11:44 ` [PATCH RFC leds + net-next 5/7] net: phy: add simple incrementing phyindex member to phy_device struct Marek Behún
2021-03-01 10:46   ` Pavel Machek
2020-10-30 11:44 ` [PATCH RFC leds + net-next 6/7] net: phy: add support for LEDs connected to ethernet PHYs Marek Behún
2021-03-01 10:52   ` Pavel Machek
2020-10-30 11:44 ` [PATCH RFC leds + net-next 7/7] net: phy: marvell: support LEDs connected on Marvell PHYs Marek Behún
2020-11-25 12:38   ` Pavel Machek [this message]
2021-03-01 11:05   ` Pavel Machek

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