tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1Ioctl Numbers
219 October 1999
3Michael Elizabeth Chastain
4<mec@shout.net>
5
6If you are adding new ioctl's to the kernel, you should use the _IO
7macros defined in <linux/ioctl.h>:
8
9 _IO an ioctl with no parameters
10 _IOW an ioctl with write parameters (copy_from_user)
11 _IOR an ioctl with read parameters (copy_to_user)
12 _IOWR an ioctl with both write and read parameters.
13
14'Write' and 'read' are from the user's point of view, just like the
15system calls 'write' and 'read'. For example, a SET_FOO ioctl would
16be _IOW, although the kernel would actually read data from user space;
17a GET_FOO ioctl would be _IOR, although the kernel would actually write
18data to user space.
19
20The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter
21or number from the table below. Because of the large number of drivers,
22many drivers share a partial letter with other drivers.
23
24If you are writing a driver for a new device and need a letter, pick an
25unused block with enough room for expansion: 32 to 256 ioctl commands.
26You can register the block by patching this file and submitting the
27patch to Linus Torvalds. Or you can e-mail me at <mec@shout.net> and
28I'll register one for you.
29
30The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number
31to distinguish ioctls from each other. The third argument to _IOW,
32_IOR, or _IOWR is the type of the data going into the kernel or coming
33out of the kernel (e.g. 'int' or 'struct foo'). NOTE! Do NOT use
34sizeof(arg) as the third argument as this results in your ioctl thinking
35it passes an argument of type size_t.
36
37Some devices use their major number as the identifier; this is OK, as
38long as it is unique. Some devices are irregular and don't follow any
39convention at all.
40
41Following this convention is good because:
42
43(1) Keeping the ioctl's globally unique helps error checking:
44 if a program calls an ioctl on the wrong device, it will get an
45 error rather than some unexpected behaviour.
46
47(2) The 'strace' build procedure automatically finds ioctl numbers
48 defined with _IO, _IOW, _IOR, or _IOWR.
49
50(3) 'strace' can decode numbers back into useful names when the
51 numbers are unique.
52
53(4) People looking for ioctls can grep for them more easily when
54 this convention is used to define the ioctl numbers.
55
56(5) When following the convention, the driver code can use generic
57 code to copy the parameters between user and kernel space.
58
59This table lists ioctls visible from user land for Linux/x86. It contains
60most drivers up to 2.6.31, but I know I am missing some. There has been
61no attempt to list non-X86 architectures or ioctls from drivers/staging/.
62
63Code Seq#(hex) Include File Comments
64========================================================
650x00 00-1F linux/fs.h conflict!
660x00 00-1F scsi/scsi_ioctl.h conflict!
670x00 00-1F linux/fb.h conflict!
680x00 00-1F linux/wavefront.h conflict!
690x02 all linux/fd.h
700x03 all linux/hdreg.h
710x04 D2-DC linux/umsdos_fs.h Dead since 2.6.11, but don't reuse these.
720x06 all linux/lp.h
730x09 all linux/raid/md_u.h
740x10 00-0F drivers/char/s390/vmcp.h
750x10 10-1F arch/s390/include/uapi/sclp_ctl.h
760x10 20-2F arch/s390/include/uapi/asm/hypfs.h
770x12 all linux/fs.h
78 linux/blkpg.h
790x1b all InfiniBand Subsystem <http://infiniband.sourceforge.net/>
800x20 all drivers/cdrom/cm206.h
810x22 all scsi/sg.h
82'#' 00-3F IEEE 1394 Subsystem Block for the entire subsystem
83'$' 00-0F linux/perf_counter.h, linux/perf_event.h
84'%' 00-0F include/uapi/linux/stm.h
85 System Trace Module subsystem
86 <mailto:alexander.shishkin@linux.intel.com>
87'&' 00-07 drivers/firewire/nosy-user.h
88'1' 00-1F <linux/timepps.h> PPS kit from Ulrich Windl
89 <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
90'2' 01-04 linux/i2o.h
91'3' 00-0F drivers/s390/char/raw3270.h conflict!
92'3' 00-1F linux/suspend_ioctls.h conflict!
93 and kernel/power/user.c
94'8' all SNP8023 advanced NIC card
95 <mailto:mcr@solidum.com>
96';' 64-7F linux/vfio.h
97'@' 00-0F linux/radeonfb.h conflict!
98'@' 00-0F drivers/video/aty/aty128fb.c conflict!
99'A' 00-1F linux/apm_bios.h conflict!
100'A' 00-0F linux/agpgart.h conflict!
101 and drivers/char/agp/compat_ioctl.h
102'A' 00-7F sound/asound.h conflict!
103'B' 00-1F linux/cciss_ioctl.h conflict!
104'B' 00-0F include/linux/pmu.h conflict!
105'B' C0-FF advanced bbus
106 <mailto:maassen@uni-freiburg.de>
107'C' all linux/soundcard.h conflict!
108'C' 01-2F linux/capi.h conflict!
109'C' F0-FF drivers/net/wan/cosa.h conflict!
110'D' all arch/s390/include/asm/dasd.h
111'D' 40-5F drivers/scsi/dpt/dtpi_ioctl.h
112'D' 05 drivers/scsi/pmcraid.h
113'E' all linux/input.h conflict!
114'E' 00-0F xen/evtchn.h conflict!
115'F' all linux/fb.h conflict!
116'F' 01-02 drivers/scsi/pmcraid.h conflict!
117'F' 20 drivers/video/fsl-diu-fb.h conflict!
118'F' 20 drivers/video/intelfb/intelfb.h conflict!
119'F' 20 linux/ivtvfb.h conflict!
120'F' 20 linux/matroxfb.h conflict!
121'F' 20 drivers/video/aty/atyfb_base.c conflict!
122'F' 00-0F video/da8xx-fb.h conflict!
123'F' 80-8F linux/arcfb.h conflict!
124'F' DD video/sstfb.h conflict!
125'G' 00-3F drivers/misc/sgi-gru/grulib.h conflict!
126'G' 00-0F linux/gigaset_dev.h conflict!
127'H' 00-7F linux/hiddev.h conflict!
128'H' 00-0F linux/hidraw.h conflict!
129'H' 01 linux/mei.h conflict!
130'H' 02 linux/mei.h conflict!
131'H' 03 linux/mei.h conflict!
132'H' 00-0F sound/asound.h conflict!
133'H' 20-40 sound/asound_fm.h conflict!
134'H' 80-8F sound/sfnt_info.h conflict!
135'H' 10-8F sound/emu10k1.h conflict!
136'H' 10-1F sound/sb16_csp.h conflict!
137'H' 10-1F sound/hda_hwdep.h conflict!
138'H' 40-4F sound/hdspm.h conflict!
139'H' 40-4F sound/hdsp.h conflict!
140'H' 90 sound/usb/usx2y/usb_stream.h
141'H' A0 uapi/linux/usb/cdc-wdm.h
142'H' C0-F0 net/bluetooth/hci.h conflict!
143'H' C0-DF net/bluetooth/hidp/hidp.h conflict!
144'H' C0-DF net/bluetooth/cmtp/cmtp.h conflict!
145'H' C0-DF net/bluetooth/bnep/bnep.h conflict!
146'H' F1 linux/hid-roccat.h <mailto:erazor_de@users.sourceforge.net>
147'H' F8-FA sound/firewire.h
148'I' all linux/isdn.h conflict!
149'I' 00-0F drivers/isdn/divert/isdn_divert.h conflict!
150'I' 40-4F linux/mISDNif.h conflict!
151'J' 00-1F drivers/scsi/gdth_ioctl.h
152'K' all linux/kd.h
153'L' 00-1F linux/loop.h conflict!
154'L' 10-1F drivers/scsi/mpt3sas/mpt3sas_ctl.h conflict!
155'L' 20-2F linux/lightnvm.h
156'L' E0-FF linux/ppdd.h encrypted disk device driver
157 <http://linux01.gwdg.de/~alatham/ppdd.html>
158'M' all linux/soundcard.h conflict!
159'M' 01-16 mtd/mtd-abi.h conflict!
160 and drivers/mtd/mtdchar.c
161'M' 01-03 drivers/scsi/megaraid/megaraid_sas.h
162'M' 00-0F drivers/video/fsl-diu-fb.h conflict!
163'N' 00-1F drivers/usb/scanner.h
164'N' 40-7F drivers/block/nvme.c
165'O' 00-06 mtd/ubi-user.h UBI
166'P' all linux/soundcard.h conflict!
167'P' 60-6F sound/sscape_ioctl.h conflict!
168'P' 00-0F drivers/usb/class/usblp.c conflict!
169'P' 01-09 drivers/misc/pci_endpoint_test.c conflict!
170'Q' all linux/soundcard.h
171'R' 00-1F linux/random.h conflict!
172'R' 01 linux/rfkill.h conflict!
173'R' C0-DF net/bluetooth/rfcomm.h
174'S' all linux/cdrom.h conflict!
175'S' 80-81 scsi/scsi_ioctl.h conflict!
176'S' 82-FF scsi/scsi.h conflict!
177'S' 00-7F sound/asequencer.h conflict!
178'T' all linux/soundcard.h conflict!
179'T' 00-AF sound/asound.h conflict!
180'T' all arch/x86/include/asm/ioctls.h conflict!
181'T' C0-DF linux/if_tun.h conflict!
182'U' all sound/asound.h conflict!
183'U' 00-CF linux/uinput.h conflict!
184'U' 00-EF linux/usbdevice_fs.h
185'U' C0-CF drivers/bluetooth/hci_uart.h
186'V' all linux/vt.h conflict!
187'V' all linux/videodev2.h conflict!
188'V' C0 linux/ivtvfb.h conflict!
189'V' C0 linux/ivtv.h conflict!
190'V' C0 media/davinci/vpfe_capture.h conflict!
191'V' C0 media/si4713.h conflict!
192'W' 00-1F linux/watchdog.h conflict!
193'W' 00-1F linux/wanrouter.h conflict! (pre 3.9)
194'W' 00-3F sound/asound.h conflict!
195'W' 40-5F drivers/pci/switch/switchtec.c
196'X' all fs/xfs/xfs_fs.h conflict!
197 and fs/xfs/linux-2.6/xfs_ioctl32.h
198 and include/linux/falloc.h
199 and linux/fs.h
200'X' all fs/ocfs2/ocfs_fs.h conflict!
201'X' 01 linux/pktcdvd.h conflict!
202'Y' all linux/cyclades.h
203'Z' 14-15 drivers/message/fusion/mptctl.h
204'[' 00-3F linux/usb/tmc.h USB Test and Measurement Devices
205 <mailto:gregkh@linuxfoundation.org>
206'a' all linux/atm*.h, linux/sonet.h ATM on linux
207 <http://lrcwww.epfl.ch/>
208'a' 00-0F drivers/crypto/qat/qat_common/adf_cfg_common.h conflict! qat driver
209'b' 00-FF conflict! bit3 vme host bridge
210 <mailto:natalia@nikhefk.nikhef.nl>
211'c' all linux/cm4000_cs.h conflict!
212'c' 00-7F linux/comstats.h conflict!
213'c' 00-7F linux/coda.h conflict!
214'c' 00-1F linux/chio.h conflict!
215'c' 80-9F arch/s390/include/asm/chsc.h conflict!
216'c' A0-AF arch/x86/include/asm/msr.h conflict!
217'd' 00-FF linux/char/drm/drm.h conflict!
218'd' 02-40 pcmcia/ds.h conflict!
219'd' F0-FF linux/digi1.h
220'e' all linux/digi1.h conflict!
221'f' 00-1F linux/ext2_fs.h conflict!
222'f' 00-1F linux/ext3_fs.h conflict!
223'f' 00-0F fs/jfs/jfs_dinode.h conflict!
224'f' 00-0F fs/ext4/ext4.h conflict!
225'f' 00-0F linux/fs.h conflict!
226'f' 00-0F fs/ocfs2/ocfs2_fs.h conflict!
227'g' 00-0F linux/usb/gadgetfs.h
228'g' 20-2F linux/usb/g_printer.h
229'h' 00-7F conflict! Charon filesystem
230 <mailto:zapman@interlan.net>
231'h' 00-1F linux/hpet.h conflict!
232'h' 80-8F fs/hfsplus/ioctl.c
233'i' 00-3F linux/i2o-dev.h conflict!
234'i' 0B-1F linux/ipmi.h conflict!
235'i' 80-8F linux/i8k.h
236'j' 00-3F linux/joystick.h
237'k' 00-0F linux/spi/spidev.h conflict!
238'k' 00-05 video/kyro.h conflict!
239'k' 10-17 linux/hsi/hsi_char.h HSI character device
240'l' 00-3F linux/tcfs_fs.h transparent cryptographic file system
241 <http://web.archive.org/web/*/http://mikonos.dia.unisa.it/tcfs>
242'l' 40-7F linux/udf_fs_i.h in development:
243 <http://sourceforge.net/projects/linux-udf/>
244'm' 00-09 linux/mmtimer.h conflict!
245'm' all linux/mtio.h conflict!
246'm' all linux/soundcard.h conflict!
247'm' all linux/synclink.h conflict!
248'm' 00-19 drivers/message/fusion/mptctl.h conflict!
249'm' 00 drivers/scsi/megaraid/megaraid_ioctl.h conflict!
250'n' 00-7F linux/ncp_fs.h and fs/ncpfs/ioctl.c
251'n' 80-8F uapi/linux/nilfs2_api.h NILFS2
252'n' E0-FF linux/matroxfb.h matroxfb
253'o' 00-1F fs/ocfs2/ocfs2_fs.h OCFS2
254'o' 00-03 mtd/ubi-user.h conflict! (OCFS2 and UBI overlaps)
255'o' 40-41 mtd/ubi-user.h UBI
256'o' 01-A1 linux/dvb/*.h DVB
257'p' 00-0F linux/phantom.h conflict! (OpenHaptics needs this)
258'p' 00-1F linux/rtc.h conflict!
259'p' 00-3F linux/mc146818rtc.h conflict!
260'p' 40-7F linux/nvram.h
261'p' 80-9F linux/ppdev.h user-space parport
262 <mailto:tim@cyberelk.net>
263'p' A1-A5 linux/pps.h LinuxPPS
264 <mailto:giometti@linux.it>
265'q' 00-1F linux/serio.h
266'q' 80-FF linux/telephony.h Internet PhoneJACK, Internet LineJACK
267 linux/ixjuser.h <http://web.archive.org/web/*/http://www.quicknet.net>
268'r' 00-1F linux/msdos_fs.h and fs/fat/dir.c
269's' all linux/cdk.h
270't' 00-7F linux/ppp-ioctl.h
271't' 80-8F linux/isdn_ppp.h
272't' 90-91 linux/toshiba.h toshiba and toshiba_acpi SMM
273'u' 00-1F linux/smb_fs.h gone
274'u' 20-3F linux/uvcvideo.h USB video class host driver
275'u' 40-4f linux/udmabuf.h userspace dma-buf misc device
276'v' 00-1F linux/ext2_fs.h conflict!
277'v' 00-1F linux/fs.h conflict!
278'v' 00-0F linux/sonypi.h conflict!
279'v' 00-0F media/v4l2-subdev.h conflict!
280'v' C0-FF linux/meye.h conflict!
281'w' all CERN SCI driver
282'y' 00-1F packet based user level communications
283 <mailto:zapman@interlan.net>
284'z' 00-3F CAN bus card conflict!
285 <mailto:hdstich@connectu.ulm.circular.de>
286'z' 40-7F CAN bus card conflict!
287 <mailto:oe@port.de>
288'z' 10-4F drivers/s390/crypto/zcrypt_api.h conflict!
289'|' 00-7F linux/media.h
2900x80 00-1F linux/fb.h
2910x89 00-06 arch/x86/include/asm/sockios.h
2920x89 0B-DF linux/sockios.h
2930x89 E0-EF linux/sockios.h SIOCPROTOPRIVATE range
2940x89 E0-EF linux/dn.h PROTOPRIVATE range
2950x89 F0-FF linux/sockios.h SIOCDEVPRIVATE range
2960x8B all linux/wireless.h
2970x8C 00-3F WiNRADiO driver
298 <http://www.winradio.com.au/>
2990x90 00 drivers/cdrom/sbpcd.h
3000x92 00-0F drivers/usb/mon/mon_bin.c
3010x93 60-7F linux/auto_fs.h
3020x94 all fs/btrfs/ioctl.h Btrfs filesystem
303 and linux/fs.h some lifted to vfs/generic
3040x97 00-7F fs/ceph/ioctl.h Ceph file system
3050x99 00-0F 537-Addinboard driver
306 <mailto:buk@buks.ipn.de>
3070xA0 all linux/sdp/sdp.h Industrial Device Project
308 <mailto:kenji@bitgate.com>
3090xA1 0 linux/vtpm_proxy.h TPM Emulator Proxy Driver
3100xA3 80-8F Port ACL in development:
311 <mailto:tlewis@mindspring.com>
3120xA3 90-9F linux/dtlk.h
3130xA4 00-1F uapi/linux/tee.h Generic TEE subsystem
3140xAA 00-3F linux/uapi/linux/userfaultfd.h
3150xAB 00-1F linux/nbd.h
3160xAC 00-1F linux/raw.h
3170xAD 00 Netfilter device in development:
318 <mailto:rusty@rustcorp.com.au>
3190xAE all linux/kvm.h Kernel-based Virtual Machine
320 <mailto:kvm@vger.kernel.org>
3210xAF 00-1F linux/fsl_hypervisor.h Freescale hypervisor
3220xB0 all RATIO devices in development:
323 <mailto:vgo@ratio.de>
3240xB1 00-1F PPPoX <mailto:mostrows@styx.uwaterloo.ca>
3250xB3 00 linux/mmc/ioctl.h
3260xB4 00-0F linux/gpio.h <mailto:linux-gpio@vger.kernel.org>
3270xB5 00-0F uapi/linux/rpmsg.h <mailto:linux-remoteproc@vger.kernel.org>
3280xB6 all linux/fpga-dfl.h
3290xC0 00-0F linux/usb/iowarrior.h
3300xCA 00-0F uapi/misc/cxl.h
3310xCA 10-2F uapi/misc/ocxl.h
3320xCA 80-BF uapi/scsi/cxlflash_ioctl.h
3330xCB 00-1F CBM serial IEC bus in development:
334 <mailto:michael.klein@puffin.lb.shuttle.de>
3350xCC 00-0F drivers/misc/ibmvmc.h pseries VMC driver
3360xCD 01 linux/reiserfs_fs.h
3370xCF 02 fs/cifs/ioctl.c
3380xDB 00-0F drivers/char/mwave/mwavepub.h
3390xDD 00-3F ZFCP device driver see drivers/s390/scsi/
340 <mailto:aherrman@de.ibm.com>
3410xE5 00-3F linux/fuse.h
3420xEC 00-01 drivers/platform/chrome/cros_ec_dev.h ChromeOS EC driver
3430xF3 00-3F drivers/usb/misc/sisusbvga/sisusb.h sisfb (in development)
344 <mailto:thomas@winischhofer.net>
3450xF4 00-1F video/mbxfb.h mbxfb
346 <mailto:raph@8d.com>
3470xF6 all LTTng Linux Trace Toolkit Next Generation
348 <mailto:mathieu.desnoyers@efficios.com>
3490xFD all linux/dm-ioctl.h