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Based on kernel version 2.6.27. Page generated on 2008-10-13 09:53 EST.

1	Ioctl Numbers
2	19 October 1999
3	Michael Elizabeth Chastain
4	<mec[AT]shout[DOT]net>
6	If you are adding new ioctl's to the kernel, you should use the _IO
7	macros defined in <linux/ioctl.h>:
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.
14	'Write' and 'read' are from the user's point of view, just like the
15	system calls 'write' and 'read'.  For example, a SET_FOO ioctl would
16	be _IOW, although the kernel would actually read data from user space;
17	a GET_FOO ioctl would be _IOR, although the kernel would actually write
18	data to user space.
20	The first argument to _IO, _IOW, _IOR, or _IOWR is an identifying letter
21	or number from the table below.  Because of the large number of drivers,
22	many drivers share a partial letter with other drivers.
24	If you are writing a driver for a new device and need a letter, pick an
25	unused block with enough room for expansion: 32 to 256 ioctl commands.
26	You can register the block by patching this file and submitting the
27	patch to Linus Torvalds.  Or you can e-mail me at <mec[AT]shout[DOT]net> and
28	I'll register one for you.
30	The second argument to _IO, _IOW, _IOR, or _IOWR is a sequence number
31	to 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
33	out of the kernel (e.g.  'int' or 'struct foo').  NOTE!  Do NOT use
34	sizeof(arg) as the third argument as this results in your ioctl thinking
35	it passes an argument of type size_t.
37	Some devices use their major number as the identifier; this is OK, as
38	long as it is unique.  Some devices are irregular and don't follow any
39	convention at all.
41	Following this convention is good because:
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.
47	(2) The 'strace' build procedure automatically finds ioctl numbers
48	    defined with _IO, _IOW, _IOR, or _IOWR.
50	(3) 'strace' can decode numbers back into useful names when the
51	    numbers are unique.
53	(4) People looking for ioctls can grep for them more easily when
54	    this convention is used to define the ioctl numbers.
56	(5) When following the convention, the driver code can use generic
57	    code to copy the parameters between user and kernel space.
59	This table lists ioctls visible from user land for Linux/i386.  It contains
60	most drivers up to 2.3.14, but I know I am missing some.
62	Code	Seq#	Include File		Comments
63	========================================================
64	0x00	00-1F	linux/fs.h		conflict!
65	0x00	00-1F	scsi/scsi_ioctl.h	conflict!
66	0x00	00-1F	linux/fb.h		conflict!
67	0x00	00-1F	linux/wavefront.h	conflict!
68	0x02	all	linux/fd.h
69	0x03	all	linux/hdreg.h
70	0x04	D2-DC	linux/umsdos_fs.h	Dead since 2.6.11, but don't reuse these.
71	0x06	all	linux/lp.h
72	0x09	all	linux/md.h
73	0x12	all	linux/fs.h
74			linux/blkpg.h
75	0x1b	all	InfiniBand Subsystem	<http://www.openib.org/>
76	0x20	all	drivers/cdrom/cm206.h
77	0x22	all	scsi/sg.h
78	'#'	00-3F	IEEE 1394 Subsystem	Block for the entire subsystem
79	'1'	00-1F	<linux/timepps.h>	PPS kit from Ulrich Windl
80						<ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
81	'8'	all				SNP8023 advanced NIC card
82						<mailto:mcr[AT]solidum[DOT]com>
83	'A'	00-1F	linux/apm_bios.h
84	'B'	C0-FF				advanced bbus
85						<mailto:maassen[AT]uni-freiburg[DOT]de>
86	'C'	all	linux/soundcard.h
87	'D'	all	asm-s390/dasd.h
88	'E'	all	linux/input.h
89	'F'	all	linux/fb.h
90	'H'	all	linux/hiddev.h
91	'I'	all	linux/isdn.h
92	'J'	00-1F	drivers/scsi/gdth_ioctl.h
93	'K'	all	linux/kd.h
94	'L'	00-1F	linux/loop.h
95	'L'	E0-FF	linux/ppdd.h		encrypted disk device driver
96						<http://linux01.gwdg.de/~alatham/ppdd.html>
97	'M'	all	linux/soundcard.h
98	'N'	00-1F	drivers/usb/scanner.h
99	'P'	all	linux/soundcard.h
100	'Q'	all	linux/soundcard.h
101	'R'	00-1F	linux/random.h
102	'S'	all	linux/cdrom.h		conflict!
103	'S'	80-81	scsi/scsi_ioctl.h	conflict!
104	'S'	82-FF	scsi/scsi.h		conflict!
105	'T'	all	linux/soundcard.h	conflict!
106	'T'	all	asm-i386/ioctls.h	conflict!
107	'U'	00-EF	linux/drivers/usb/usb.h
108	'V'	all	linux/vt.h
109	'W'	00-1F	linux/watchdog.h	conflict!
110	'W'	00-1F	linux/wanrouter.h	conflict!
111	'X'	all	linux/xfs_fs.h
112	'Y'	all	linux/cyclades.h
113	'a'	all				ATM on linux
114						<http://lrcwww.epfl.ch/linux-atm/magic.html>
115	'b'	00-FF				bit3 vme host bridge
116						<mailto:natalia[AT]nikhefk.nikhef[DOT]nl>
117	'c'	00-7F	linux/comstats.h	conflict!
118	'c'	00-7F	linux/coda.h		conflict!
119	'c'	80-9F	asm-s390/chsc.h
120	'd'	00-FF	linux/char/drm/drm/h	conflict!
121	'd'	00-DF	linux/video_decoder.h	conflict!
122	'd'	F0-FF	linux/digi1.h
123	'e'	all	linux/digi1.h		conflict!
124	'e'	00-1F	linux/video_encoder.h	conflict!
125	'e'	00-1F	net/irda/irtty.h	conflict!
126	'f'	00-1F	linux/ext2_fs.h
127	'h'	00-7F				Charon filesystem
128						<mailto:zapman[AT]interlan[DOT]net>
129	'i'	00-3F	linux/i2o.h
130	'j'	00-3F	linux/joystick.h
131	'l'	00-3F	linux/tcfs_fs.h		transparent cryptographic file system
132						<http://mikonos.dia.unisa.it/tcfs>
133	'l'	40-7F	linux/udf_fs_i.h	in development:
134						<http://sourceforge.net/projects/linux-udf/>
135	'm'	all	linux/mtio.h		conflict!
136	'm'	all	linux/soundcard.h	conflict!
137	'm'	all	linux/synclink.h	conflict!
138	'm'	00-1F	net/irda/irmod.h	conflict!
139	'n'	00-7F	linux/ncp_fs.h
140	'n'	E0-FF	video/matrox.h          matroxfb
141	'o'	00-1F	fs/ocfs2/ocfs2_fs.h	OCFS2
142	'p'	00-0F	linux/phantom.h		conflict! (OpenHaptics needs this)
143	'p'	00-3F	linux/mc146818rtc.h	conflict!
144	'p'	40-7F	linux/nvram.h
145	'p'	80-9F				user-space parport
146						<mailto:tim[AT]cyberelk[DOT]net>
147	'q'	00-1F	linux/serio.h
148	'q'	80-FF				Internet PhoneJACK, Internet LineJACK
149						<http://www.quicknet.net>
150	'r'	00-1F	linux/msdos_fs.h
151	's'	all	linux/cdk.h
152	't'	00-7F	linux/if_ppp.h
153	't'	80-8F	linux/isdn_ppp.h
154	'u'	00-1F	linux/smb_fs.h
155	'v'	00-1F	linux/ext2_fs.h		conflict!
156	'v'	all	linux/videodev.h	conflict!
157	'w'	all				CERN SCI driver
158	'y'	00-1F				packet based user level communications
159						<mailto:zapman[AT]interlan[DOT]net>
160	'z'	00-3F				CAN bus card
161						<mailto:hdstich[AT]connectu.ulm.circular[DOT]de>
162	'z'	40-7F				CAN bus card
163						<mailto:oe[AT]port[DOT]de>
164	0x80	00-1F	linux/fb.h
165	0x81	00-1F	linux/videotext.h
166	0x89	00-06	asm-i386/sockios.h
167	0x89	0B-DF	linux/sockios.h
168	0x89	E0-EF	linux/sockios.h		SIOCPROTOPRIVATE range
169	0x89	F0-FF	linux/sockios.h		SIOCDEVPRIVATE range
170	0x8B	all	linux/wireless.h
171	0x8C	00-3F				WiNRADiO driver
172						<http://www.proximity.com.au/~brian/winradio/>
173	0x90	00	drivers/cdrom/sbpcd.h
174	0x93	60-7F	linux/auto_fs.h
175	0x99	00-0F				537-Addinboard driver
176						<mailto:buk[AT]buks.ipn[DOT]de>
177	0xA0	all	linux/sdp/sdp.h		Industrial Device Project
178						<mailto:kenji[AT]bitgate[DOT]com>
179	0xA3	80-8F	Port ACL		in development:
180						<mailto:tlewis[AT]mindspring[DOT]com>
181	0xA3	90-9F	linux/dtlk.h
182	0xAB	00-1F	linux/nbd.h
183	0xAC	00-1F	linux/raw.h
184	0xAD	00	Netfilter device	in development:
185						<mailto:rusty[AT]rustcorp.com[DOT]au>	
186	0xAE	all	linux/kvm.h		Kernel-based Virtual Machine
187						<mailto:kvm-devel[AT]lists.sourceforge[DOT]net>
188	0xB0	all	RATIO devices		in development:
189						<mailto:vgo[AT]ratio[DOT]de>
190	0xB1	00-1F	PPPoX			<mailto:mostrows[AT]styx.uwaterloo[DOT]ca>
191	0xCB	00-1F	CBM serial IEC bus	in development:
192						<mailto:michael.klein[AT]puffin.lb.shuttle[DOT]de>
193	0xDD	00-3F	ZFCP device driver	see drivers/s390/scsi/
194						<mailto:aherrman[AT]de.ibm[DOT]com>
195	0xF3	00-3F	video/sisfb.h		sisfb (in development)
196						<mailto:thomas[AT]winischhofer[DOT]net>
197	0xF4	00-1F	video/mbxfb.h		mbxfb
198						<mailto:raph[AT]8d[DOT]com>
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