Re: [PATCH led-next 1/1] leds: mlxreg: Allow multi-instantiation of same name LED for modular systems

[Pavel Machek <pavel@ucw.cz>]

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Hi!

> > > But why you consider it as function enumerator?
> > > For example card48, card56 are two different devices of same type.
> > > Both have 'status' LED.
> > 
> > OK this is a fair point.
> > 
> > I was thinking such because in my mind I had this idea that for an ethernet
> > switch with interfaces lan0 - lan4 it would make sense to use the
> > LED_FUNCTION_LAN function with function enumerator. But thinking about
> > this now again makes me wonder if instead the lan0 - lan4 should be
> > devicenames instead, since normally they are network interface names.
> > 
> > Vadim, the reason why Pavel and I think that mlxreg (or mlxregN) is not
> > valid devicename part (although mlxreg has to stay since many users
> > already depend on it, as you say), is that the mlxreg name is not exposed
> > anywhere else in Linux from userspace point of view.
> > 
> > Devicename eth0 is okay, because it is network interface name.
> > Devicename sda would be okay, because everyone knows it is a block device
> > and you can access it via /dev/sda.
> > Devicename hci0 would be okay because it is bluetooth interface accessible
> > via hcitool.
> > Devicenames mtd0, kbd0, mouse0 would be okay, I think.
> > 
> > But mlxreg is not accessible via anything else in the system. Unless your
> > systems also have something like /dev/mlxreg, that is.
> > 
> > Do the LEDs on these cards only indicate status of the cards themselves as a
> > whole? Or are there LEDs on these cards dedicated to their peripherals? For
> > example if there is an ethernet port with LEDs on one of these cards, the
> > devicename part for these LEDs should be of the device of that ethernet
> > port, not mlxreg...
> 
> Hi Marek,
> 
> Each line card must have 'status' LED, indicating status of line card itself.
> User can set non-green in case some there are some alarms on different devices,
> equipped on this line card. It can be set blink during line card initialization.
> 
> Line card could be equipped with UID LED. User can set this LED in order to
> find physical location of line card. Sometimes it's hard to see the sticker on
> chassis.
> 
> Line card also equipped with per port LED, but those LEDs are handled by FW.
> 
> So, the device in this case is 'line card'.
> 
> In my previous reply I suggest name 'fru' stands for the filed replaceable unit.
> This is not something, that is exposed in '/dev', but it describes any replaceable
> unit within the system.

So.. you'd use the LED to locate right PCI card, or the LED would
indicate that whole card is failing, etc...?

Could we use pci00:1b.0 as the device name? (same as lspci). Probably
replace : with _...

Best regards,
								Pavel
-- 
http://www.livejournal.com/~pavelmachek

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