=============
Ioctl Numbers
=============

19 October 1999

Michael Elizabeth Chastain
<mec@shout.net>

If you are adding new ioctl's to the kernel, you should use the _IO
macros defined in <linux/ioctl.h>:

    ====== ===========================
    macro  parameters
    ====== ===========================
    _IO    none
    _IOW   write (read from userspace)
    _IOR   read (write to userpace)
    _IOWR  write and read
    ====== ===========================

'Write' and 'read' are from the user's point of view, just like the
system calls 'write' and 'read'.  For example, a SET_FOO ioctl would
be _IOW, although the kernel would actually read data from user space;
a GET_FOO ioctl would be _IOR, although the kernel would actually write
data to user space.

The first argument to the macros is an identifying letter or number from
the table below. Because of the large number of drivers, many drivers
share a partial letter with other drivers.

If you are writing a driver for a new device and need a letter, pick an
unused block with enough room for expansion: 32 to 256 ioctl commands
should suffice. You can register the block by patching this file and
submitting the patch through :doc:`usual patch submission process
</process/submitting-patches>`.

The second argument is a sequence number to distinguish ioctls from each
other. The third argument (not applicable to _IO) is the type of the data
going into the kernel or coming out of the kernel (e.g.  'int' or
'struct foo').

.. note::
   Do NOT use sizeof(arg) as the third argument as this results in your
   ioctl thinking it passes an argument of type size_t.

Some devices use their major number as the identifier; this is OK, as
long as it is unique.  Some devices are irregular and don't follow any
convention at all.

Following this convention is good because:

(1) Keeping the ioctl's globally unique helps error checking:
    if a program calls an ioctl on the wrong device, it will get an
    error rather than some unexpected behaviour.

(2) The 'strace' build procedure automatically finds ioctl numbers
    defined with the macros.

(3) 'strace' can decode numbers back into useful names when the
    numbers are unique.

(4) People looking for ioctls can grep for them more easily when
    this convention is used to define the ioctl numbers.

(5) When following the convention, the driver code can use generic
    code to copy the parameters between user and kernel space.

This table lists ioctls visible from userland, excluding ones from
drivers/staging/.

====  =====  ========================================================= ================================================================
Code  Seq#    Include File                                             Comments
      (hex)
====  =====  ========================================================= ================================================================
0x00  00-1F  linux/fs.h                                                conflict!
0x00  00-1F  scsi/scsi_ioctl.h                                         conflict!
0x00  00-1F  linux/fb.h                                                conflict!
0x00  00-1F  linux/wavefront.h                                         conflict!
0x02  all    linux/fd.h
0x03  all    linux/hdreg.h
0x04  D2-DC  linux/umsdos_fs.h                                         Dead since 2.6.11, but don't reuse these.
0x06  all    linux/lp.h
0x07  9F-D0  linux/vmw_vmci_defs.h, uapi/linux/vm_sockets.h
0x09  all    linux/raid/md_u.h
0x10  00-0F  drivers/char/s390/vmcp.h
0x10  10-1F  arch/s390/include/uapi/sclp_ctl.h
0x10  20-2F  arch/s390/include/uapi/asm/hypfs.h
0x12  all    linux/fs.h                                                BLK* ioctls
             linux/blkpg.h
             linux/blkzoned.h
             linux/blk-crypto.h
0x15  all    linux/fs.h                                                FS_IOC_* ioctls
0x1b  all                                                              InfiniBand Subsystem
                                                                       <http://infiniband.sourceforge.net/>
0x20  all    drivers/cdrom/cm206.h
0x22  all    scsi/sg.h
0x3E  00-0F  linux/counter.h                                           <mailto:linux-iio@vger.kernel.org>
'!'   00-1F  uapi/linux/seccomp.h
'#'   00-3F                                                            IEEE 1394 Subsystem
                                                                       Block for the entire subsystem
'$'   00-0F  linux/perf_counter.h, linux/perf_event.h
'%'   00-0F  include/uapi/linux/stm.h                                  System Trace Module subsystem
                                                                       <mailto:alexander.shishkin@linux.intel.com>
'&'   00-07  drivers/firewire/nosy-user.h
'*'   00-1F  uapi/linux/user_events.h                                  User Events Subsystem
                                                                       <mailto:linux-trace-kernel@vger.kernel.org>
'1'   00-1F  linux/timepps.h                                           PPS kit from Ulrich Windl
                                                                       <ftp://ftp.de.kernel.org/pub/linux/daemons/ntp/PPS/>
'2'   01-04  linux/i2o.h
'3'   00-0F  drivers/s390/char/raw3270.h                               conflict!
'3'   00-1F  linux/suspend_ioctls.h,                                   conflict!
             kernel/power/user.c
'8'   all                                                              SNP8023 advanced NIC card
                                                                       <mailto:mcr@solidum.com>
';'   64-7F  linux/vfio.h
';'   80-FF  linux/iommufd.h
'='   00-3f  uapi/linux/ptp_clock.h                                    <mailto:richardcochran@gmail.com>
'@'   00-0F  linux/radeonfb.h                                          conflict!
'@'   00-0F  drivers/video/aty/aty128fb.c                              conflict!
'A'   00-1F  linux/apm_bios.h                                          conflict!
'A'   00-0F  linux/agpgart.h,                                          conflict!
             drivers/char/agp/compat_ioctl.h
'A'   00-7F  sound/asound.h                                            conflict!
'B'   00-1F  linux/cciss_ioctl.h                                       conflict!
'B'   00-0F  include/linux/pmu.h                                       conflict!
'B'   C0-FF  advanced bbus                                             <mailto:maassen@uni-freiburg.de>
'B'   00-0F  xen/xenbus_dev.h                                          conflict!
'C'   all    linux/soundcard.h                                         conflict!
'C'   01-2F  linux/capi.h                                              conflict!
'C'   F0-FF  drivers/net/wan/cosa.h                                    conflict!
'D'   all    arch/s390/include/asm/dasd.h
'D'   40-5F  drivers/scsi/dpt/dtpi_ioctl.h                             Dead since 2022
'D'   05     drivers/scsi/pmcraid.h
'E'   all    linux/input.h                                             conflict!
'E'   00-0F  xen/evtchn.h                                              conflict!
'F'   all    linux/fb.h                                                conflict!
'F'   01-02  drivers/scsi/pmcraid.h                                    conflict!
'F'   20     drivers/video/fsl-diu-fb.h                                conflict!
'F'   20     linux/ivtvfb.h                                            conflict!
'F'   20     linux/matroxfb.h                                          conflict!
'F'   20     drivers/video/aty/atyfb_base.c                            conflict!
'F'   00-0F  video/da8xx-fb.h                                          conflict!
'F'   80-8F  linux/arcfb.h                                             conflict!
'F'   DD     video/sstfb.h                                             conflict!
'G'   00-3F  drivers/misc/sgi-gru/grulib.h                             conflict!
'G'   00-0F  xen/gntalloc.h, xen/gntdev.h                              conflict!
'H'   00-7F  linux/hiddev.h                                            conflict!
'H'   00-0F  linux/hidraw.h                                            conflict!
'H'   01     linux/mei.h                                               conflict!
'H'   02     linux/mei.h                                               conflict!
'H'   03     linux/mei.h                                               conflict!
'H'   00-0F  sound/asound.h                                            conflict!
'H'   20-40  sound/asound_fm.h                                         conflict!
'H'   80-8F  sound/sfnt_info.h                                         conflict!
'H'   10-8F  sound/emu10k1.h                                           conflict!
'H'   10-1F  sound/sb16_csp.h                                          conflict!
'H'   10-1F  sound/hda_hwdep.h                                         conflict!
'H'   40-4F  sound/hdspm.h                                             conflict!
'H'   40-4F  sound/hdsp.h                                              conflict!
'H'   90     sound/usb/usx2y/usb_stream.h
'H'   00-0F  uapi/misc/habanalabs.h                                    conflict!
'H'   A0     uapi/linux/usb/cdc-wdm.h
'H'   C0-F0  net/bluetooth/hci.h                                       conflict!
'H'   C0-DF  net/bluetooth/hidp/hidp.h                                 conflict!
'H'   C0-DF  net/bluetooth/cmtp/cmtp.h                                 conflict!
'H'   C0-DF  net/bluetooth/bnep/bnep.h                                 conflict!
'H'   F1     linux/hid-roccat.h                                        <mailto:erazor_de@users.sourceforge.net>
'H'   F8-FA  sound/firewire.h
'I'   all    linux/isdn.h                                              conflict!
'I'   00-0F  drivers/isdn/divert/isdn_divert.h                         conflict!
'I'   40-4F  linux/mISDNif.h                                           conflict!
'K'   all    linux/kd.h
'L'   00-1F  linux/loop.h                                              conflict!
'L'   10-1F  drivers/scsi/mpt3sas/mpt3sas_ctl.h                        conflict!
'L'   E0-FF  linux/ppdd.h                                              encrypted disk device driver
                                                                       <http://linux01.gwdg.de/~alatham/ppdd.html>
'M'   all    linux/soundcard.h                                         conflict!
'M'   01-16  mtd/mtd-abi.h                                             conflict!
      and    drivers/mtd/mtdchar.c
'M'   01-03  drivers/scsi/megaraid/megaraid_sas.h
'M'   00-0F  drivers/video/fsl-diu-fb.h                                conflict!
'N'   00-1F  drivers/usb/scanner.h
'N'   40-7F  drivers/block/nvme.c
'N'   80-8F  uapi/linux/ntsync.h                                       NT synchronization primitives
                                                                       <mailto:wine-devel@winehq.org>
'O'   00-06  mtd/ubi-user.h                                            UBI
'P'   all    linux/soundcard.h                                         conflict!
'P'   60-6F  sound/sscape_ioctl.h                                      conflict!
'P'   00-0F  drivers/usb/class/usblp.c                                 conflict!
'P'   01-09  drivers/misc/pci_endpoint_test.c                          conflict!
'P'   00-0F  xen/privcmd.h                                             conflict!
'P'   00-05  linux/tps6594_pfsm.h                                      conflict!
'Q'   all    linux/soundcard.h
'R'   00-1F  linux/random.h                                            conflict!
'R'   01     linux/rfkill.h                                            conflict!
'R'   20-2F  linux/trace_mmap.h
'R'   C0-DF  net/bluetooth/rfcomm.h
'R'   E0     uapi/linux/fsl_mc.h
'S'   all    linux/cdrom.h                                             conflict!
'S'   80-81  scsi/scsi_ioctl.h                                         conflict!
'S'   82-FF  scsi/scsi.h                                               conflict!
'S'   00-7F  sound/asequencer.h                                        conflict!
'T'   all    linux/soundcard.h                                         conflict!
'T'   00-AF  sound/asound.h                                            conflict!
'T'   all    arch/x86/include/asm/ioctls.h                             conflict!
'T'   C0-DF  linux/if_tun.h                                            conflict!
'U'   all    sound/asound.h                                            conflict!
'U'   00-CF  linux/uinput.h                                            conflict!
'U'   00-EF  linux/usbdevice_fs.h
'U'   C0-CF  drivers/bluetooth/hci_uart.h
'V'   all    linux/vt.h                                                conflict!
'V'   all    linux/videodev2.h                                         conflict!
'V'   C0     linux/ivtvfb.h                                            conflict!
'V'   C0     linux/ivtv.h                                              conflict!
'V'   C0     media/si4713.h                                            conflict!
'W'   00-1F  linux/watchdog.h                                          conflict!
'W'   00-1F  linux/wanrouter.h                                         conflict! (pre 3.9)
'W'   00-3F  sound/asound.h                                            conflict!
'W'   40-5F  drivers/pci/switch/switchtec.c
'W'   60-61  linux/watch_queue.h
'X'   all    fs/xfs/xfs_fs.h,                                          conflict!
             fs/xfs/linux-2.6/xfs_ioctl32.h,
             include/linux/falloc.h,
             linux/fs.h,
'X'   all    fs/ocfs2/ocfs_fs.h                                        conflict!
'Z'   14-15  drivers/message/fusion/mptctl.h
'['   00-3F  linux/usb/tmc.h                                           USB Test and Measurement Devices
                                                                       <mailto:gregkh@linuxfoundation.org>
'a'   all    linux/atm*.h, linux/sonet.h                               ATM on linux
                                                                       <http://lrcwww.epfl.ch/>
'a'   00-0F  drivers/crypto/qat/qat_common/adf_cfg_common.h            conflict! qat driver
'b'   00-FF                                                            conflict! bit3 vme host bridge
                                                                       <mailto:natalia@nikhefk.nikhef.nl>
'b'   00-0F  linux/dma-buf.h                                           conflict!
'c'   00-7F  linux/comstats.h                                          conflict!
'c'   00-7F  linux/coda.h                                              conflict!
'c'   00-1F  linux/chio.h                                              conflict!
'c'   80-9F  arch/s390/include/asm/chsc.h                              conflict!
'c'   A0-AF  arch/x86/include/asm/msr.h conflict!
'd'   00-FF  linux/char/drm/drm.h                                      conflict!
'd'   02-40  pcmcia/ds.h                                               conflict!
'd'   F0-FF  linux/digi1.h
'e'   all    linux/digi1.h                                             conflict!
'f'   00-1F  linux/ext2_fs.h                                           conflict!
'f'   00-1F  linux/ext3_fs.h                                           conflict!
'f'   00-0F  fs/jfs/jfs_dinode.h                                       conflict!
'f'   00-0F  fs/ext4/ext4.h                                            conflict!
'f'   00-0F  linux/fs.h                                                conflict!
'f'   00-0F  fs/ocfs2/ocfs2_fs.h                                       conflict!
'f'   13-27  linux/fscrypt.h
'f'   81-8F  linux/fsverity.h
'g'   00-0F  linux/usb/gadgetfs.h
'g'   20-2F  linux/usb/g_printer.h
'h'   00-7F                                                            conflict! Charon filesystem
                                                                       <mailto:zapman@interlan.net>
'h'   00-1F  linux/hpet.h                                              conflict!
'h'   80-8F  fs/hfsplus/ioctl.c
'i'   00-3F  linux/i2o-dev.h                                           conflict!
'i'   0B-1F  linux/ipmi.h                                              conflict!
'i'   80-8F  linux/i8k.h
'i'   90-9F  `linux/iio/*.h`                                           IIO
'j'   00-3F  linux/joystick.h
'k'   00-0F  linux/spi/spidev.h                                        conflict!
'k'   00-05  video/kyro.h                                              conflict!
'k'   10-17  linux/hsi/hsi_char.h                                      HSI character device
'l'   00-3F  linux/tcfs_fs.h                                           transparent cryptographic file system
                                                                       <http://web.archive.org/web/%2A/http://mikonos.dia.unisa.it/tcfs>
'l'   40-7F  linux/udf_fs_i.h                                          in development:
                                                                       <https://github.com/pali/udftools>
'm'   00-09  linux/mmtimer.h                                           conflict!
'm'   all    linux/mtio.h                                              conflict!
'm'   all    linux/soundcard.h                                         conflict!
'm'   all    linux/synclink.h                                          conflict!
'm'   00-19  drivers/message/fusion/mptctl.h                           conflict!
'm'   00     drivers/scsi/megaraid/megaraid_ioctl.h                    conflict!
'n'   00-7F  linux/ncp_fs.h and fs/ncpfs/ioctl.c
'n'   80-8F  uapi/linux/nilfs2_api.h                                   NILFS2
'n'   E0-FF  linux/matroxfb.h                                          matroxfb
'o'   00-1F  fs/ocfs2/ocfs2_fs.h                                       OCFS2
'o'   00-03  mtd/ubi-user.h                                            conflict! (OCFS2 and UBI overlaps)
'o'   40-41  mtd/ubi-user.h                                            UBI
'o'   01-A1  `linux/dvb/*.h`                                           DVB
'p'   00-0F  linux/phantom.h                                           conflict! (OpenHaptics needs this)
'p'   00-1F  linux/rtc.h                                               conflict!
'p'   40-7F  linux/nvram.h
'p'   80-9F  linux/ppdev.h                                             user-space parport
                                                                       <mailto:tim@cyberelk.net>
'p'   A1-A5  linux/pps.h                                               LinuxPPS
'p'   B1-B3  linux/pps_gen.h                                           LinuxPPS
                                                                       <mailto:giometti@linux.it>
'q'   00-1F  linux/serio.h
'q'   80-FF  linux/telephony.h                                         Internet PhoneJACK, Internet LineJACK
             linux/ixjuser.h                                           <http://web.archive.org/web/%2A/http://www.quicknet.net>
'r'   00-1F  linux/msdos_fs.h and fs/fat/dir.c
's'   all    linux/cdk.h
't'   00-7F  linux/ppp-ioctl.h
't'   80-8F  linux/isdn_ppp.h
't'   90-91  linux/toshiba.h                                           toshiba and toshiba_acpi SMM
'u'   00-1F  linux/smb_fs.h                                            gone
'u'   00-2F  linux/ublk_cmd.h                                          conflict!
'u'   20-3F  linux/uvcvideo.h                                          USB video class host driver
'u'   40-4f  linux/udmabuf.h                                           userspace dma-buf misc device
'v'   00-1F  linux/ext2_fs.h                                           conflict!
'v'   00-1F  linux/fs.h                                                conflict!
'v'   00-0F  linux/sonypi.h                                            conflict!
'v'   00-0F  media/v4l2-subdev.h                                       conflict!
'v'   20-27  arch/powerpc/include/uapi/asm/vas-api.h                   VAS API
'v'   C0-FF  linux/meye.h                                              conflict!
'w'   all                                                              CERN SCI driver
'y'   00-1F                                                            packet based user level communications
                                                                       <mailto:zapman@interlan.net>
'z'   00-3F                                                            CAN bus card conflict!
                                                                       <mailto:hdstich@connectu.ulm.circular.de>
'z'   40-7F                                                            CAN bus card conflict!
                                                                       <mailto:oe@port.de>
'z'   10-4F  drivers/s390/crypto/zcrypt_api.h                          conflict!
'|'   00-7F  linux/media.h
'|'   80-9F  samples/                                                  Any sample and example drivers
0x80  00-1F  linux/fb.h
0x81  00-1F  linux/vduse.h
0x89  00-06  arch/x86/include/asm/sockios.h
0x89  0B-DF  linux/sockios.h
0x89  E0-EF  linux/sockios.h                                           SIOCPROTOPRIVATE range
0x89  F0-FF  linux/sockios.h                                           SIOCDEVPRIVATE range
0x8A  00-1F  linux/eventpoll.h
0x8B  all    linux/wireless.h
0x8C  00-3F                                                            WiNRADiO driver
                                                                       <http://www.winradio.com.au/>
0x90  00     drivers/cdrom/sbpcd.h
0x92  00-0F  drivers/usb/mon/mon_bin.c
0x93  60-7F  linux/auto_fs.h
0x94  all    fs/btrfs/ioctl.h                                          Btrfs filesystem
             and linux/fs.h                                            some lifted to vfs/generic
0x97  00-7F  fs/ceph/ioctl.h                                           Ceph file system
0x99  00-0F                                                            537-Addinboard driver
                                                                       <mailto:buk@buks.ipn.de>
0x9A  00-0F  include/uapi/fwctl/fwctl.h
0xA0  all    linux/sdp/sdp.h                                           Industrial Device Project
                                                                       <mailto:kenji@bitgate.com>
0xA1  0      linux/vtpm_proxy.h                                        TPM Emulator Proxy Driver
0xA2  all    uapi/linux/acrn.h                                         ACRN hypervisor
0xA3  80-8F                                                            Port ACL  in development:
                                                                       <mailto:tlewis@mindspring.com>
0xA3  90-9F  linux/dtlk.h
0xA4  00-1F  uapi/linux/tee.h                                          Generic TEE subsystem
0xA4  00-1F  uapi/asm/sgx.h                                            <mailto:linux-sgx@vger.kernel.org>
0xA5  01-05  linux/surface_aggregator/cdev.h                           Microsoft Surface Platform System Aggregator
                                                                       <mailto:luzmaximilian@gmail.com>
0xA5  20-2F  linux/surface_aggregator/dtx.h                            Microsoft Surface DTX driver
                                                                       <mailto:luzmaximilian@gmail.com>
0xAA  00-3F  linux/uapi/linux/userfaultfd.h
0xAB  00-1F  linux/nbd.h
0xAC  00-1F  linux/raw.h
0xAD  00                                                               Netfilter device in development:
                                                                       <mailto:rusty@rustcorp.com.au>
0xAE  00-1F  linux/kvm.h                                               Kernel-based Virtual Machine
                                                                       <mailto:kvm@vger.kernel.org>
0xAE  40-FF  linux/kvm.h                                               Kernel-based Virtual Machine
                                                                       <mailto:kvm@vger.kernel.org>
0xAE  20-3F  linux/nitro_enclaves.h                                    Nitro Enclaves
0xAF  00-1F  linux/fsl_hypervisor.h                                    Freescale hypervisor
0xB0  all                                                              RATIO devices in development:
                                                                       <mailto:vgo@ratio.de>
0xB1  00-1F                                                            PPPoX
                                                                       <mailto:mostrows@styx.uwaterloo.ca>
0xB2  00     arch/powerpc/include/uapi/asm/papr-vpd.h                  powerpc/pseries VPD API
                                                                       <mailto:linuxppc-dev@lists.ozlabs.org>
0xB2  01-02  arch/powerpc/include/uapi/asm/papr-sysparm.h              powerpc/pseries system parameter API
                                                                       <mailto:linuxppc-dev@lists.ozlabs.org>
0xB2  03-05  arch/powerpc/include/uapi/asm/papr-indices.h              powerpc/pseries indices API
                                                                       <mailto:linuxppc-dev@lists.ozlabs.org>
0xB2  06-07  arch/powerpc/include/uapi/asm/papr-platform-dump.h        powerpc/pseries Platform Dump API
                                                                       <mailto:linuxppc-dev@lists.ozlabs.org>
0xB2  08     arch/powerpc/include/uapi/asm/papr-physical-attestation.h powerpc/pseries Physical Attestation API
                                                                       <mailto:linuxppc-dev@lists.ozlabs.org>
0xB2  09     arch/powerpc/include/uapi/asm/papr-hvpipe.h               powerpc/pseries HVPIPE API
                                                                       <mailto:linuxppc-dev@lists.ozlabs.org>
0xB3  00     linux/mmc/ioctl.h
0xB4  00-0F  linux/gpio.h                                              <mailto:linux-gpio@vger.kernel.org>
0xB5  00-0F  uapi/linux/rpmsg.h                                        <mailto:linux-remoteproc@vger.kernel.org>
0xB6  all    linux/fpga-dfl.h
0xB7  all    uapi/linux/remoteproc_cdev.h                              <mailto:linux-remoteproc@vger.kernel.org>
0xB7  all    uapi/linux/nsfs.h                                         <mailto:Andrei Vagin <avagin@openvz.org>>
0xB8  01-02  uapi/misc/mrvl_cn10k_dpi.h                                Marvell CN10K DPI driver
0xB8  all    uapi/linux/mshv.h                                         Microsoft Hyper-V /dev/mshv driver
                                                                       <mailto:linux-hyperv@vger.kernel.org>
0xC0  00-0F  linux/usb/iowarrior.h
0xCA  00-0F  uapi/misc/cxl.h                                           Dead since 6.15
0xCA  10-2F  uapi/misc/ocxl.h
0xCA  80-BF  uapi/scsi/cxlflash_ioctl.h                                Dead since 6.15
0xCB  00-1F                                                            CBM serial IEC bus in development:
                                                                       <mailto:michael.klein@puffin.lb.shuttle.de>
0xCC  00-0F  drivers/misc/ibmvmc.h                                     pseries VMC driver
0xCD  01     linux/reiserfs_fs.h                                       Dead since 6.13
0xCE  01-02  uapi/linux/cxl_mem.h                                      Compute Express Link Memory Devices
0xCF  02     fs/smb/client/cifs_ioctl.h
0xDB  00-0F  drivers/char/mwave/mwavepub.h
0xDD  00-3F                                                            ZFCP device driver see drivers/s390/scsi/
                                                                       <mailto:aherrman@de.ibm.com>
0xE5  00-3F  linux/fuse.h
0xEC  00-01  drivers/platform/chrome/cros_ec_dev.h                     ChromeOS EC driver
0xEE  00-09  uapi/linux/pfrut.h                                        Platform Firmware Runtime Update and Telemetry
0xF3  00-3F  drivers/usb/misc/sisusbvga/sisusb.h                       sisfb (in development)
                                                                       <mailto:thomas@winischhofer.net>
0xF6  all                                                              LTTng Linux Trace Toolkit Next Generation
                                                                       <mailto:mathieu.desnoyers@efficios.com>
0xF8  all    arch/x86/include/uapi/asm/amd_hsmp.h                      AMD HSMP EPYC system management interface driver
                                                                       <mailto:nchatrad@amd.com>
0xF9  00-0F  uapi/misc/amd-apml.h                                      AMD side band system management interface driver
                                                                       <mailto:naveenkrishna.chatradhi@amd.com>
0xFD  all    linux/dm-ioctl.h
0xFE  all    linux/isst_if.h
====  =====  ========================================================= ================================================================
