^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 1) .. SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 3) =======================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) Notes on Linux SCSI Generic (sg) driver
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) =======================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) 20020126
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) Introduction
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) ============
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) The SCSI Generic driver (sg) is one of the four "high level" SCSI device
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) drivers along with sd, st and sr (disk, tape and CDROM respectively). Sg
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) is more generalized (but lower level) than its siblings and tends to be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) used on SCSI devices that don't fit into the already serviced categories.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) Thus sg is used for scanners, CD writers and reading audio CDs digitally
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) amongst other things.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) Rather than document the driver's interface here, version information
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) is provided plus pointers (i.e. URLs) where to find documentation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) and examples.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) Major versions of the sg driver
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) ===============================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) There are three major versions of sg found in the linux kernel (lk):
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) - sg version 1 (original) from 1992 to early 1999 (lk 2.2.5) .
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) It is based in the sg_header interface structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) - sg version 2 from lk 2.2.6 in the 2.2 series. It is based on
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) an extended version of the sg_header interface structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) - sg version 3 found in the lk 2.4 series (and the lk 2.5 series).
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) It adds the sg_io_hdr interface structure.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) Sg driver documentation
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) =======================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) The most recent documentation of the sg driver is kept at the Linux
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) Documentation Project's (LDP) site:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) - http://www.tldp.org/HOWTO/SCSI-Generic-HOWTO
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) This describes the sg version 3 driver found in the lk 2.4 series.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) The LDP renders documents in single and multiple page HTML, postscript
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) and pdf. This document can also be found at:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) - http://sg.danny.cz/sg/p/sg_v3_ho.html
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) Documentation for the version 2 sg driver found in the lk 2.2 series can
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49) be found at http://sg.danny.cz/sg/. A larger version
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) is at: http://sg.danny.cz/sg/p/scsi-generic_long.txt.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) The original documentation for the sg driver (prior to lk 2.2.6) can be
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) found at http://www.torque.net/sg/p/original/SCSI-Programming-HOWTO.txt
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) and in the LDP archives.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) A changelog with brief notes can be found in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) /usr/src/linux/include/scsi/sg.h file. Note that the glibc maintainers copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) and edit this file (removing its changelog for example) before placing it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) in /usr/include/scsi/sg.h . Driver debugging information and other notes
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) can be found at the top of the /usr/src/linux/drivers/scsi/sg.c file.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) A more general description of the Linux SCSI subsystem of which sg is a
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) part can be found at http://www.tldp.org/HOWTO/SCSI-2.4-HOWTO .
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) Example code and utilities
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) ==========================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) There are two packages of sg utilities:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) ========= ==========================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) sg3_utils for the sg version 3 driver found in lk 2.4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) sg_utils for the sg version 2 (and original) driver found in lk 2.2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) and earlier
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) ========= ==========================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76) Both packages will work in the lk 2.4 series however sg3_utils offers more
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) capabilities. They can be found at: http://sg.danny.cz/sg/sg3_utils.html and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) freecode.com
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) Another approach is to look at the applications that use the sg driver.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) These include cdrecord, cdparanoia, SANE and cdrdao.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) Mapping of Linux kernel versions to sg driver versions
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85) ======================================================
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) Here is a list of linux kernels in the 2.4 series that had new version
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) of the sg driver:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) - lk 2.4.0 : sg version 3.1.17
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) - lk 2.4.7 : sg version 3.1.19
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) - lk 2.4.10 : sg version 3.1.20 [#]_
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) - lk 2.4.17 : sg version 3.1.22
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) .. [#] There were 3 changes to sg version 3.1.20 by third parties in the
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) next six linux kernel versions.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97) For reference here is a list of linux kernels in the 2.2 series that had
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) new version of the sg driver:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) - lk 2.2.0 : original sg version [with no version number]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) - lk 2.2.6 : sg version 2.1.31
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) - lk 2.2.8 : sg version 2.1.32
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) - lk 2.2.10 : sg version 2.1.34 [SG_GET_VERSION_NUM ioctl first appeared]
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) - lk 2.2.14 : sg version 2.1.36
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) - lk 2.2.16 : sg version 2.1.38
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) - lk 2.2.17 : sg version 2.1.39
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) - lk 2.2.20 : sg version 2.1.40
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) The lk 2.5 development series has recently commenced and it currently
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) contains sg version 3.5.23 which is functionally equivalent to sg
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) version 3.1.22 found in lk 2.4.17.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) Douglas Gilbert
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 26th January 2002
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) dgilbert@interlog.com
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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