sysfs Class Coverage Ledger
Overview
This ledger inventories sysfs classes with two independent, honestly scoped sources, and the Source column records which of them vouches for each row:
live@5.10.134— the class directory exists in/sys/class/on the host this encyclopedia was built on (kernel 5.10.134, Alibaba Cloudkangaroobuild, x86_64). Device counts are the momentary population of this container host and will differ on your machine. Live presence proves existence for that kernel configuration only — a driver built as module and not loaded, or disabled via config, removes the class entirely.ABI-doc— the class hasWhat: /sys/class/<name>/...entries in the kernel’sDocumentation/ABI/tree (torvalds/linux master). This is the kernel project itself promising an interface, but not every class is documented there (absence from ABI-doc is not absence from sysfs), and documented attributes may still vary by driver.
Neither source alone, and not their union, is a complete list of every class any Linux kernel can expose — that set is configuration-dependent by design (see sysfs overview). The Attrs column counts distinct documented attribute paths found in ABI docs, a lower bound on the attributes a class may expose; drivers routinely add their own.
Status vocabulary (defined in the encyclopedia overview):
not-started → inventoried only · researched → sources read ·
documented → full class page with attribute semantics, permissions,
version/config notes, safe inspection examples and write warnings ·
source-limited → documented with fewer sources than the standard.
Classes
| ID | Class | Source | Live devices | Documented attrs | Status | Chapter | Notes |
|---|---|---|---|---|---|---|---|
| SYSC-accel | accel | ABI-doc | — | 34 | source-limited | ./classes/accel.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-ata_device | ata_device | ABI-doc | — | 9 | documented | ./classes/ata_device.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-ata_link | ata_link | ABI-doc | — | 3 | documented | ./classes/ata_link.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-ata_port | ata_port | ABI-doc | — | 3 | documented | ./classes/ata_port.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-backlight | backlight | live@5.10.134 + ABI-doc | 0 | 15 | documented | — | —ABI |
| SYSC-bdi | bdi | live@5.10.134 + ABI-doc | 9 | 10 | documented | — | —Full |
| SYSC-block | block | live@5.10.134 + ABI-doc | 4 | 171 | documented | — | —Full |
| SYSC-bluetooth | bluetooth | ABI-doc | — | 3 | documented | — | —chapter |
| SYSC-bsg | bsg | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-bsr | bsr | ABI-doc | — | 3 | documented | ./classes/bsr.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-c2port | c2port | ABI-doc | — | 11 | documented | ./classes/c2port.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-chromeos | chromeos | ABI-doc | — | 14 | documented | ./classes/chromeos.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-cpuid | cpuid | live@5.10.134 | 2 | 0 | documented | — | —chapter |
| SYSC-cxl | cxl | ABI-doc | — | 23 | documented | ./classes/cxl.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-devfreq | devfreq | ABI-doc | — | 14 | documented | ./classes/devfreq.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-devfreq-event | devfreq-event | ABI-doc | — | 3 | documented | ./classes/devfreq-event.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-devlink | devlink | live@5.10.134 + ABI-doc | 0 | 7 | documented | — | —chapter |
| SYSC-drm | drm | live@5.10.134 + ABI-doc | 1 | 1 | documented | — | —chapter |
| SYSC-extcon | extcon | ABI-doc | — | 6 | documented | ./classes/extcon.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-fc | fc | ABI-doc | — | 1 | documented | ./classes/fc.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-fc_host | fc_host | ABI-doc | — | 3 | documented | ./classes/fc_host.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-fc_remote_ports | fc_remote_ports | ABI-doc | — | 3 | documented | ./classes/fc_remote_ports.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-firmware | firmware | ABI-doc | — | 7 | documented | — | —chapter |
| SYSC-firmware-attributes | firmware-attributes | ABI-doc | — | 11 | documented | ./classes/firmware-attributes.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-fpga_bridge | fpga_bridge | ABI-doc | — | 2 | documented | — | —chapter |
| SYSC-fpga_manager | fpga_manager | ABI-doc | — | 3 | documented | — | —chapter |
| SYSC-fpga_region | fpga_region | ABI-doc | — | 1 | documented | — | —chapter |
| SYSC-genwqe | genwqe | ABI-doc | — | 12 | documented | ./classes/genwqe.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-gism_class | gism_class | live@5.10.134 | 1 | 0 | source-limited | ./classes/gism_class.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-gnss | gnss | ABI-doc | — | 1 | documented | ./classes/gnss.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-gpio | gpio | ABI-doc | — | 1 | documented | — | —DEPRECATED: |
| SYSC-graphics | graphics | live@5.10.134 | 1 | 0 | documented | — | —chapter |
| SYSC-hidraw | hidraw | ABI-doc | — | 2 | documented | ./classes/hidraw.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-hwmon | hwmon | live@5.10.134 + ABI-doc | 0 | 120 | documented | — | —ABI |
| SYSC-i2c-adapter | i2c-adapter | live@5.10.134 | 0 | 0 | documented | — | —no |
| SYSC-ieee80211 | ieee80211 | ABI-doc | — | 2 | source-limited | ./classes/ieee80211.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-infiniband | infiniband | ABI-doc | — | 122 | documented | — | —chapter |
| SYSC-infiniband_mad | infiniband_mad | ABI-doc | — | 5 | documented | — | —chapter |
| SYSC-infiniband_srp | infiniband_srp | ABI-doc | — | 3 | documented | — | —chapter |
| SYSC-infiniband_verbs | infiniband_verbs | ABI-doc | — | 3 | documented | — | —chapter |
| SYSC-input | input | live@5.10.134 + ABI-doc | 2 | 3 | documented | — | —chapter |
| SYSC-intel_pmt | intel_pmt | ABI-doc | — | 14 | documented | ./classes/intel_pmt.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-iommu | iommu | live@5.10.134 + ABI-doc | 0 | 7 | documented | ./classes/iommu.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-iscsi_connection | iscsi_connection | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-iscsi_endpoint | iscsi_endpoint | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-iscsi_host | iscsi_host | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-iscsi_iface | iscsi_iface | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-iscsi_session | iscsi_session | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-iscsi_transport | iscsi_transport | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-issei | issei | ABI-doc | — | 9 | documented | ./classes/issei.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-lcd | lcd | ABI-doc | — | 3 | documented | ./classes/lcd.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-leds | leds | ABI-doc | — | 96 | documented | — | —ABI |
| SYSC-macvtap | macvtap | live@5.10.134 | 0 | 0 | source-limited | ./classes/macvtap.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-mdio_bus | mdio_bus | ABI-doc | — | 16 | documented | ./classes/mdio_bus.md | ——chapter |
| SYSC-mei | mei | ABI-doc | — | 10 | documented | ./classes/mei.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-mem | mem | live@5.10.134 | 8 | 0 | documented | — | —chapter |
| SYSC-mic | mic | ABI-doc | — | 13 | documented | ./classes/mic.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-misc | misc | live@5.10.134 + ABI-doc | 75 | 2 | documented | — | —chapter |
| SYSC-msr | msr | live@5.10.134 | 2 | 0 | documented | — | —chapter |
| SYSC-mtd | mtd | ABI-doc | — | 22 | documented | — | —chapter |
| SYSC-mux | mux | ABI-doc | — | 2 | documented | ./classes/mux.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-nd | nd | live@5.10.134 | 1 | 0 | documented | — | —chapter |
| SYSC-net | net | live@5.10.134 + ABI-doc | 3 | 96 | documented | — | —Full |
| SYSC-nvme | nvme | live@5.10.134 + ABI-doc | 0 | 39 | documented | — | —Entry |
| SYSC-nvme-generic | nvme-generic | live@5.10.134 | 0 | 0 | source-limited | ./classes/nvme-generic.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-nvme-subsystem | nvme-subsystem | live@5.10.134 + ABI-doc | 0 | 6 | documented | ./classes/nvme-subsystem.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-ocxl | ocxl | ABI-doc | — | 1 | documented | ./classes/ocxl.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-pci_bus | pci_bus | live@5.10.134 | 0 | 0 | source-limited | ./classes/pci_bus.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-platform-profile | platform-profile | ABI-doc | — | 3 | documented | ./classes/platform-profile.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-power | power | ABI-doc | — | 2 | source-limited | ./classes/power.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-power_supply | power_supply | live@5.10.134 + ABI-doc | 0 | 82 | documented | — | —ABI |
| SYSC-powercap | powercap | ABI-doc | — | 3 | documented | ./classes/powercap.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-pps | pps | live@5.10.134 + ABI-doc | 0 | 8 | documented | ./classes/pps.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-pps-gen | pps-gen | ABI-doc | — | 6 | documented | ./classes/pps-gen.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-ptp | ptp | live@5.10.134 + ABI-doc | 1 | 16 | documented | ./classes/ptp.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-pwm | pwm | ABI-doc | — | 11 | documented | — | —ABI |
| SYSC-rapidio_port | rapidio_port | ABI-doc | — | 2 | documented | ./classes/rapidio_port.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rc | rc | ABI-doc | — | 9 | documented | ./classes/rc.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-reboot-mode | reboot-mode | ABI-doc | — | 1 | documented | ./classes/reboot-mode.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-regulator | regulator | ABI-doc | — | 33 | documented | — | —ABI |
| SYSC-remoteproc | remoteproc | ABI-doc | — | 5 | documented | ./classes/remoteproc.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rfkill | rfkill | ABI-doc | — | 7 | documented | ./classes/rfkill.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rnbd-client | rnbd-client | ABI-doc | — | 2 | documented | ./classes/rnbd-client.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rnbd-server | rnbd-server | ABI-doc | — | 7 | documented | ./classes/rnbd-server.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rtc | rtc | ABI-doc | — | 12 | documented | ./classes/rtc.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rtrs-client | rtrs-client | ABI-doc | — | 17 | documented | ./classes/rtrs-client.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-rtrs-server | rtrs-server | ABI-doc | — | 7 | documented | ./classes/rtrs-server.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-scsi_device | scsi_device | live@5.10.134 + ABI-doc | 0 | 15 | documented | ./classes/scsi_device.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-scsi_disk | scsi_disk | live@5.10.134 | 0 | 0 | source-limited | ./classes/scsi_disk.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-scsi_generic | scsi_generic | live@5.10.134 | 0 | 0 | source-limited | ./classes/scsi_generic.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-scsi_host | scsi_host | live@5.10.134 + ABI-doc | 0 | 26 | documented | ./classes/scsi_host.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-scsi_tape | scsi_tape | ABI-doc | — | 10 | documented | ./classes/scsi_tape.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-spi_master | spi_master | ABI-doc | — | 5 | documented | ./classes/spi_master.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-srp_remote_ports | srp_remote_ports | ABI-doc | — | 7 | documented | ./classes/srp_remote_ports.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-stm | stm | ABI-doc | — | 3 | documented | ./classes/stm.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-stm_source | stm_source | ABI-doc | — | 1 | documented | ./classes/stm_source.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-switchtec | switchtec | ABI-doc | — | 10 | documented | ./classes/switchtec.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-tee | tee | ABI-doc | — | 2 | documented | ./classes/tee.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-thermal | thermal | live@5.10.134 + ABI-doc | 0 | 27 | documented | — | —ABI |
| SYSC-timecard | timecard | ABI-doc | — | 37 | documented | ./classes/timecard.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-tpm | tpm | live@5.10.134 + ABI-doc | 0 | 20 | documented | ./classes/tpm.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-tpmrm | tpmrm | live@5.10.134 | 0 | 0 | source-limited | ./classes/tpmrm.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-tsm | tsm | ABI-doc | — | 1 | source-limited | ./classes/tsm.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-tty | tty | live@5.10.134 + ABI-doc | 70 | 17 | documented | — | —Full |
| SYSC-typec | typec | ABI-doc | — | 36 | documented | ./classes/typec.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-uacce | uacce | ABI-doc | — | 8 | documented | ./classes/uacce.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-ubi | ubi | ABI-doc | — | 25 | documented | ./classes/ubi.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-ubiX | ubiX | ABI-doc | — | 1 | documented | ./classes/ubiX.md | —wave 7-b page: ABI-sourced attribute table; device-dir layout sibling of ubi.md |
| SYSC-udc | udc | ABI-doc | — | 12 | documented | ./classes/udc.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-uio | uio | live@5.10.134 | 0 | 0 | documented | ./classes/uio.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-usb_power_delivery | usb_power_delivery | ABI-doc | — | 36 | documented | ./classes/usb_power_delivery.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-usb_role | usb_role | ABI-doc | — | 3 | documented | ./classes/usb_role.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-vc | vc | live@5.10.134 | 6 | 0 | source-limited | — | —No |
| SYSC-vduse | vduse | ABI-doc | — | 4 | documented | ./classes/vduse.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-virtio-ports | virtio-ports | live@5.10.134 | 0 | 0 | documented | — | —chapter |
| SYSC-vtconsole | vtconsole | live@5.10.134 | 1 | 0 | source-limited | ./classes/vtconsole.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-vvu | vvu | live@5.10.134 | 0 | 0 | source-limited | ./classes/vvu.md | —wave 7-b page: honest stub, thin/no ABI sources |
| SYSC-wakeup | wakeup | ABI-doc | — | 11 | documented | ./classes/wakeup.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-watchdog | watchdog | ABI-doc | — | 13 | documented | ./classes/watchdog.md | —wave 7-b page: ABI-sourced attribute table |
| SYSC-zram-control | zram-control | live@5.10.134 + ABI-doc | 2 | 3 | documented | ./classes/zram-control.md | —wave 7-b page: ABI-sourced attribute table |
Total classes: 120 (live: 46, ABI-documented: 95).
sysfs interfaces that are not classes
The kernel also exposes structured state at other sysfs locations. These are
tracked here so they are not misclassified as classes (see the
overview for the taxonomy and how /sys/class symlinks
relate to /sys/devices):
| Prefix | Documented paths (count) | Chapter | Notes |
|---|---|---|---|
/sys/bus/* | 60 | — | — |
/sys/devices/* | 19 | — | — |
/sys/firmware/* | 19 | — | — |
/sys/fs/* | 12 | — | — |
/sys/kernel/* | 35 | — | — |
/sys/module/* | 7 | — | — |