netdev - Re: [PATCH iwl-next v2] igc: Add support for LEDs on i225/i226

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Date: Thu, 01 Feb 2024 14:52:41 +0100
From: Kurt Kanzenbach <kurt@...utronix.de>
To: Andrew Lunn <andrew@...n.ch>
Cc: Jesse Brandeburg <jesse.brandeburg@...el.com>, Tony Nguyen
 <anthony.l.nguyen@...el.com>, Vinicius Costa Gomes
 <vinicius.gomes@...el.com>, "David S. Miller" <davem@...emloft.net>, Eric
 Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo
 Abeni <pabeni@...hat.com>, intel-wired-lan@...ts.osuosl.org,
 netdev@...r.kernel.org, Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Subject: Re: [PATCH iwl-next v2] igc: Add support for LEDs on i225/i226

On Thu Feb 01 2024, Andrew Lunn wrote:
> On Thu, Feb 01, 2024 at 01:59:46PM +0100, Kurt Kanzenbach wrote:
>> Add support for LEDs on i225/i226. The LEDs can be controlled via sysfs
>> from user space using the netdev trigger. The LEDs are named as
>> igc-<bus><device>-<led> to be easily identified.
>> 
>> Offloading link speed is supported. Other modes are simulated in software
>> by using on/off. Tested on Intel i225.
>> 
>> Signed-off-by: Kurt Kanzenbach <kurt@...utronix.de>
>> ---
>> 
>> Changes since v1:
>> 
>>  * Add brightness_set() to allow software control (Andrew)
>>  * Remove offloading of activity, because the software control is more flexible
>
> Please could you expand on that. Activity is quite expensive in
> software, since it needs to get the statistics every 50ms and then
> control the LED. So if activity can be offloaded, it should
> be. Sometimes the hardware can only offload a subset of activity
> indications, which is fine. It should implement those it can, and
> leave the rest to software.

Activity can be offloaded to HW only with Tx and Rx combined. Individual
Rx or Tx activity is not supported. But sure, when a user selects Rx and
Tx it can be offloaded, if it's too expensive doing it in software.

Thanks,
Kurt

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