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From: Heiner Kallweit <hkallweit1@gmail.com>
To: "Marek Behún" <kabel@kernel.org>
Cc: Michael Walle <michael@walle.cc>,
	andrew@lunn.ch, anthony.l.nguyen@intel.com,
	bigeasy@linutronix.de, davem@davemloft.net,
	dvorax.fuxbrumer@linux.intel.com, f.fainelli@gmail.com,
	jacek.anaszewski@gmail.com, kuba@kernel.org, kurt@linutronix.de,
	linux-leds@vger.kernel.org, netdev@vger.kernel.org, pavel@ucw.cz,
	sasha.neftin@intel.com, vinicius.gomes@intel.com,
	vitaly.lifshits@intel.com
Subject: Re: [PATCH net-next 5/5] igc: Export LEDs
Date: Thu, 29 Jul 2021 23:54:09 +0200	[thread overview]
Message-ID: <3495aa83-75eb-bb89-f3c8-f6f829f3d243@gmail.com> (raw)
In-Reply-To: <20210729105901.35a73431@thinkpad>

On 29.07.2021 10:59, Marek Behún wrote:
> Hello Heiner,
> 
> On Wed, 28 Jul 2021 22:43:30 +0200
> Heiner Kallweit <hkallweit1@gmail.com> wrote:
> 
>> Did we come to any conclusion?
>>
>> My preliminary r8169 implementation now creates the following LED names:
>>
>> lrwxrwxrwx 1 root root 0 Jul 26 22:50 r8169-led0-0300 -> ../../devices/pci0000:00/0000:00:1d.0/0000:03:00.0/net/enp3s0/r8169-led0-0300
>> lrwxrwxrwx 1 root root 0 Jul 26 22:50 r8169-led1-0300 -> ../../devices/pci0000:00/0000:00:1d.0/0000:03:00.0/net/enp3s0/r8169-led1-0300
>> lrwxrwxrwx 1 root root 0 Jul 26 22:50 r8169-led2-0300 -> ../../devices/pci0000:00/0000:00:1d.0/0000:03:00.0/net/enp3s0/r8169-led2-0300
>>
>> I understood that LEDs should at least be renamed to r8169-0300::link-0
>> to link-2 Is this correct? Or do we have to wait with any network LED support
>> for a name discussion outcome?
> 
> I would expect some of the LEDs to, by default, indicate activity.
> So maybe look at the settings BIOS left, and if the setting is to
> indicate link, use the "link" function, and if activity, use the
> "activity" function? 
> 

The function may be changed by the user. Then what? Rename the LED device?
A typical use case is also that one LED indicates both, link and activity.

>> For the different LED modes I defined private hw triggers (using trigger_type
>> to make the triggers usable with r8169 LEDs only). The trigger attribute now
>> looks like this:
>>
>> [none] link_10_100 link_1000 link_10_100_1000 link_ACT link_10_100_ACT link_1000_ACT link_10_100_1000_ACT
>>
>> Nice, or? Issue is just that these trigger names really should be made a
>> standard for all network LEDs. I don't care about the exact naming, important
>> is just that trigger names are the same, no matter whether it's about a r8169-
>> or igc- or whatever network chip controlled LEDs.
> 
> This is how I at first proposed doing this, last year. But this is
> WRONG!
> 
> First, we do not want a different trigger for each possible
> configuration. We want one trigger, and then choose configuration via
> other sysfs file. I.e. a "hw" trigger, which, when activated, would
> create sysfs files "link" and "act", via which you can configure those
> options.
> 
> Second, we already have a standard LED trigger for network devices,
> netdev! So what we should do is use the netdev trigger, and offload
> blinking to the LED controller if it supports it. The problems with
> this are:
> 1. not yet implemented in upstream, see my latest version
>    https://lore.kernel.org/linux-leds/20210601005155.27997-1-kabel@kernel.org/
> 2. netdev trigger currently does not support all these different link
>    functions. We have these settings:
>      device_name: network interface name, i.e. eth0
>      link: 0 - do not indicate link
>            1 - indicate link (ON when linked)
>      tx: 0 - do not blink on transmit
>          1 - blink on transmit
>      rx: 0 - do not blink on receive
>          1 - blink on receive
>      interval: duration of LED blink in ms
> 
> I would like to extend netdev trigger to support different
> configurations. Currently my ideas are as follows:
> - a new sysfs file, "advanced", will show up when netdev trigger is
>   enabled (and if support is compiled in)
> - when advanced is set to 1, for each possible link mode (10base-t,
>   100base-t, 1000base-t, ...) a new sysfs directory will show up, and

This leads to new questions like: How do you know what the possible
link modes are? In a spare minute you could have a look at enum
ethtool_link_mode_bit_indices. Even with standard multi-gig hw
meanwhile you have: 10M, 100M, 1G, 2.5G, 5G, 10G.
Supposedly the information about possible link modes would have to be
stored in led_classdev so that it can generate the appropriate sysfs
directories during registration.

>   in each of these directories the following files:
>     rx, tx, link, interval, brightness
>     multi_intensity (if the LED is a multi-color LED)
>   and possibly even
>     pattern
> With this, the user can configure more complicated configurations:
> - different LED color for different link speeds
> - different blink speed for different link speeds
> And if some of the configurations are offloadable to the HW, the drivers
> can be written to support such offloading. (Maybe even add a read-only
> file "offloaded" to indicate if the trigger was offloaded.)
> 

For a fully hw-offloaded LED like in my case then more or less the only
benefit of led_classdev + netdev trigger is the unified location of
link speed + tx/rx attributes. The brightness attribute has no meaning
because brightness can't be controlled.
Overall quite some overhead for a small functionality. At least in a
simple case like mine I'd use custom attributes under the net_dev like
this if I had to invent something on my own:
led0/speed: where you can say: "echo +100 > led0/speed" to enable 100M link indication
led0/activity: bool

> I will work on these ideas in the following weeks and will sent
> proposals to linux-leds.
> 

I don't want to be the one always saying: Nice framework, but heh:
How about my special case xyz?

I understand that it can be a frustrating job, that needs quite some
patience, to create a framework that you consider to be clean and
that covers the needs of (almost) everybody. I failed with some early
attempts to establish RGB LED support using the HSV color model.

>> And I don't have a good solution for initialization yet. LED mode is whatever
>> BIOS sets, but initial trigger value is "none". I would have to read the
>> initial LED control register values, iterate over the triggers to find the
>> matching one, and call led_trigger_set() to properly set this trigger as
>> current trigger.
> 
> You can set led_cdev->default_trigger prior registering the LED. But
> this is moot: we do not want a different trigger for each PHY interface
> mode.
> 
> Marek
> 

  reply	other threads:[~2021-07-29 21:54 UTC|newest]

Thread overview: 68+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-16 21:24 [PATCH net-next 0/5][pull request] 1GbE Intel Wired LAN Driver Updates 2021-07-16 Tony Nguyen
2021-07-16 21:24 ` [PATCH net-next 1/5] igc: Add possibility to add flex filter Tony Nguyen
2021-07-16 21:24 ` [PATCH net-next 2/5] igc: Integrate flex filter into ethtool ops Tony Nguyen
2021-07-16 21:24 ` [PATCH net-next 3/5] igc: Allow for Flex Filters to be installed Tony Nguyen
2021-07-16 21:24 ` [PATCH net-next 4/5] igc: Make flex filter more flexible Tony Nguyen
2021-07-16 21:24 ` [PATCH net-next 5/5] igc: Export LEDs Tony Nguyen
2021-07-16 21:56   ` Andrew Lunn
2021-07-18 22:10     ` Heiner Kallweit
2021-07-18 22:33       ` Andrew Lunn
2021-07-19  6:17         ` Kurt Kanzenbach
2021-07-19  9:46           ` Jakub Kicinski
2021-07-19  6:06     ` Kurt Kanzenbach
2021-07-19 13:15       ` Andrew Lunn
2021-07-20  8:54         ` Kurt Kanzenbach
2021-07-21 19:18         ` Marek Behún
2021-07-18 22:19   ` Heiner Kallweit
2021-07-19  0:40     ` Andrew Lunn
2021-07-20 15:00       ` Heiner Kallweit
2021-07-20 15:42         ` Andrew Lunn
2021-07-20 20:29           ` Heiner Kallweit
2021-07-21 14:35             ` Andrew Lunn
2021-07-21 16:02               ` Heiner Kallweit
2021-07-21 18:23               ` Pavel Machek
2021-07-21 18:25                 ` Pavel Machek
2021-07-21 18:45             ` Marek Behún
2021-07-21 19:50               ` Andrew Lunn
2021-07-21 20:07                 ` Marek Behún
2021-07-21 20:54                   ` Andrew Lunn
2021-07-21 21:31                     ` Marek Behún
2021-07-21 22:45                     ` Pavel Machek
2021-07-22  1:45                       ` Andrew Lunn
2021-07-22  2:19                         ` Marek Behún
2021-07-21 22:34                   ` Pavel Machek
2021-07-22  3:52                   ` Florian Fainelli
2021-07-26 17:42                   ` Jacek Anaszewski
2021-07-26 18:44                     ` Marek Behún
2021-07-26 20:59                     ` Heiner Kallweit
2021-07-27  0:06                       ` Marek Behún
2021-07-27  1:57                         ` Andrew Lunn
2021-07-27  8:15                           ` Michael Walle
2021-07-27 14:56                             ` Marek Behún
2021-07-27 15:03                               ` Michael Walle
2021-07-27 15:24                                 ` Andrew Lunn
2021-07-27 15:28                                 ` Marek Behún
2021-07-27 15:53                                   ` Michael Walle
2021-07-27 16:23                                     ` Andrew Lunn
2021-07-27 16:32                                     ` Marek Behún
2021-07-27 16:42                                       ` Andrew Lunn
2021-07-27 19:42                                       ` Michael Walle
2021-07-28 20:43                                       ` Heiner Kallweit
2021-07-29  6:39                                         ` Kurt Kanzenbach
2021-07-29  8:59                                         ` Marek Behún
2021-07-29 21:54                                           ` Heiner Kallweit [this message]
2021-08-10 17:29                                         ` Pavel Machek
2021-08-10 17:55                                           ` Marek Behún
2021-08-10 19:53                                             ` Pavel Machek
2021-08-10 20:53                                               ` Marek Behún
2021-08-17 19:02                                                 ` Pavel Machek
2021-08-25 15:26                                                   ` Marek Behún
2021-08-26 12:45                                                     ` Pavel Machek
2021-08-10 20:46                                           ` Heiner Kallweit
2021-08-10 21:21                                             ` Andrew Lunn
2021-07-27 13:55                           ` Marek Behún
2021-08-10 17:22                             ` Documentation for naming LEDs was " Pavel Machek
2021-07-19 21:48   ` Jesse Brandeburg
2021-07-20 13:31     ` Kurt Kanzenbach
2021-07-17  0:30 ` [PATCH net-next 0/5][pull request] 1GbE Intel Wired LAN Driver Updates 2021-07-16 patchwork-bot+netdevbpf
2021-07-17 17:36   ` Andrew Lunn

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