> diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci > index ecf47559f495..93d22b779d20 100644 > --- a/Documentation/ABI/testing/sysfs-bus-pci > +++ b/Documentation/ABI/testing/sysfs-bus-pci > @@ -500,3 +500,66 @@ Description: > console drivers from the device. Raw users of pci-sysfs > resourceN attributes must be terminated prior to resizing. > Success of the resizing operation is not guaranteed. > + > +What: /sys/bus/pci/devices/.../leds/*:enclosure:*/brightness > +What: /sys/class/leds/*:enclosure:*/brightness > +Date: August 2024 > +KernelVersion: 6.12 > +Description: > + LED indications on PCIe storage enclosures which are controlled > + through the NPEM interface (Native PCIe Enclosure Management, > + PCIe r6.1 sec 6.28) are accessible as led class devices, both s/led/LED/ preferably. > + below /sys/class/leds and below NPEM-capable PCI devices. > + > + Although these led class devices could be manipulated manually, ditto > + in practice they are typically manipulated automatically by an > + application such as ledmon(8). > + > + The name of a led class device is as follows: an LED > + <bdf>:enclosure:<indication> > + where: > + > + - <bdf> is the domain, bus, device and function number > + (e.g. 10000:02:05.0) > + - <indication> is a short description of the LED indication > + > + Valid indications per PCIe r6.1 table 6-27 are: > + > + - ok (drive is functioning normally) > + - locate (drive is being identified by an admin) > + - fail (drive is not functioning properly) > + - rebuild (drive is part of an array that is rebuilding) > + - pfa (drive is predicted to fail soon) > + - hotspare (drive is marked to be used as a replacement) > + - ica (drive is part of an array that is degraded) > + - ifa (drive is part of an array that is failed) > + - idt (drive is not the right type for the connector) > + - disabled (drive is disabled, removal is safe) > + - specific0 to specific7 (enclosure-specific indications) > + > + Broadly, the indications fall into one of these categories: > + > + - to signify drive state (ok, locate, fail, idt, disabled) > + - to signify drive role or state in a software RAID array > + (rebuild, pfa, hotspare, ica, ifa) > + - to signify any other role or state (specific0 to specific7) > + > + Mandatory indications per PCIe r6.1 sec 7.9.19.2 comprise: > + ok, locate, fail, rebuild. All others are optional. > + A led class device is only visible if the corresponding An LED > + indication is supported by the device. > + > + To manipulate the indications, write 0 (LED_OFF) or 1 (LED_ON) > + to the "brightness" file. Note that manipulating an indication > + may implicitly manipulate other indications at the vendor's > + discretion. E.g. when the user lights up the "ok" indication, > + the vendor may choose to automatically turn off the "fail" > + indication. The current state of an indication can be > + retrieved by reading its "brightness" file. > + > + The PCIe Base Specification allows vendors leeway to choose > + different colors or blinking patterns for the indications, > + but they typically follow the IBPI standard. E.g. the "locate" > + indication is usually presented as one or two LEDs blinking at > + 4 Hz frequency: > + https://en.wikipedia.org/wiki/International_Blinking_Pattern_Interpretation -- ~Randy
