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Linus Torvalds1da177e2005-04-16 15:20:36 -07001This driver is for Compaq's SMART Array Controllers.
2
3Supported Cards:
4----------------
5
6This driver is known to work with the following cards:
7
8 * SA 5300
9 * SA 5i
10 * SA 532
11 * SA 5312
12 * SA 641
13 * SA 642
14 * SA 6400
15 * SA 6400 U320 Expansion Module
16 * SA 6i
17 * SA P600
18 * SA P800
19 * SA E400
Mike Miller3de0a702005-06-27 14:36:48 -070020 * SA E300
Linus Torvalds1da177e2005-04-16 15:20:36 -070021
22If nodes are not already created in the /dev/cciss directory, run as root:
23
24# cd /dev
25# ./MAKEDEV cciss
26
27Device Naming:
28--------------
29
30You need some entries in /dev for the cciss device. The MAKEDEV script
31can make device nodes for you automatically. Currently the device setup
32is as follows:
33
34Major numbers:
35 104 cciss0
36 105 cciss1
37 106 cciss2
38 105 cciss3
39 108 cciss4
40 109 cciss5
41 110 cciss6
42 111 cciss7
43
44Minor numbers:
45 b7 b6 b5 b4 b3 b2 b1 b0
46 |----+----| |----+----|
47 | |
48 | +-------- Partition ID (0=wholedev, 1-15 partition)
49 |
50 +-------------------- Logical Volume number
51
52The device naming scheme is:
53/dev/cciss/c0d0 Controller 0, disk 0, whole device
54/dev/cciss/c0d0p1 Controller 0, disk 0, partition 1
55/dev/cciss/c0d0p2 Controller 0, disk 0, partition 2
56/dev/cciss/c0d0p3 Controller 0, disk 0, partition 3
57
58/dev/cciss/c1d1 Controller 1, disk 1, whole device
59/dev/cciss/c1d1p1 Controller 1, disk 1, partition 1
60/dev/cciss/c1d1p2 Controller 1, disk 1, partition 2
61/dev/cciss/c1d1p3 Controller 1, disk 1, partition 3
62
63SCSI tape drive and medium changer support
64------------------------------------------
65
66SCSI sequential access devices and medium changer devices are supported and
67appropriate device nodes are automatically created. (e.g.
68/dev/st0, /dev/st1, etc. See the "st" man page for more details.)
69You must enable "SCSI tape drive support for Smart Array 5xxx" and
70"SCSI support" in your kernel configuration to be able to use SCSI
71tape drives with your Smart Array 5xxx controller.
72
73Additionally, note that the driver will not engage the SCSI core at init
74time. The driver must be directed to dynamically engage the SCSI core via
75the /proc filesystem entry which the "block" side of the driver creates as
76/proc/driver/cciss/cciss* at runtime. This is because at driver init time,
77the SCSI core may not yet be initialized (because the driver is a block
78driver) and attempting to register it with the SCSI core in such a case
79would cause a hang. This is best done via an initialization script
80(typically in /etc/init.d, but could vary depending on distibution).
81For example:
82
83 for x in /proc/driver/cciss/cciss[0-9]*
84 do
85 echo "engage scsi" > $x
86 done
87
88Once the SCSI core is engaged by the driver, it cannot be disengaged
89(except by unloading the driver, if it happens to be linked as a module.)
90
91Note also that if no sequential access devices or medium changers are
92detected, the SCSI core will not be engaged by the action of the above
93script.
94
95Hot plug support for SCSI tape drives
96-------------------------------------
97
98Hot plugging of SCSI tape drives is supported, with some caveats.
99The cciss driver must be informed that changes to the SCSI bus
100have been made, in addition to and prior to informing the SCSI
101mid layer. This may be done via the /proc filesystem. For example:
102
103 echo "rescan" > /proc/scsi/cciss0/1
104
105This causes the adapter to query the adapter about changes to the
106physical SCSI buses and/or fibre channel arbitrated loop and the
107driver to make note of any new or removed sequential access devices
108or medium changers. The driver will output messages indicating what
109devices have been added or removed and the controller, bus, target and
110lun used to address the device. Once this is done, the SCSI mid layer
111can be informed of changes to the virtual SCSI bus which the driver
112presents to it in the usual way. For example:
113
114 echo scsi add-single-device 3 2 1 0 > /proc/scsi/scsi
115
116to add a device on controller 3, bus 2, target 1, lun 0. Note that
117the driver makes an effort to preserve the devices positions
118in the virtual SCSI bus, so if you are only moving tape drives
119around on the same adapter and not adding or removing tape drives
120from the adapter, informing the SCSI mid layer may not be necessary.
121
122Note that the naming convention of the /proc filesystem entries
123contains a number in addition to the driver name. (E.g. "cciss0"
124instead of just "cciss" which you might expect.)
125
126Note: ONLY sequential access devices and medium changers are presented
127as SCSI devices to the SCSI mid layer by the cciss driver. Specifically,
128physical SCSI disk drives are NOT presented to the SCSI mid layer. The
129physical SCSI disk drives are controlled directly by the array controller
130hardware and it is important to prevent the kernel from attempting to directly
131access these devices too, as if the array controller were merely a SCSI
132controller in the same way that we are allowing it to access SCSI tape drives.
133