Root/Documentation/scsi/qlogicfas.txt

1
2This driver supports the Qlogic FASXXX family of chips. This driver
3only works with the ISA, VLB, and PCMCIA versions of the Qlogic
4FastSCSI! cards as well as any other card based on the FASXX chip
5(including the Control Concepts SCSI/IDE/SIO/PIO/FDC cards).
6
7This driver does NOT support the PCI version. Support for these PCI
8Qlogic boards:
9
10    * IQ-PCI
11    * IQ-PCI-10
12    * IQ-PCI-D
13
14is provided by the qla1280 driver.
15
16Nor does it support the PCI-Basic, which is supported by the
17'am53c974' driver.
18
19PCMCIA SUPPORT
20
21This currently only works if the card is enabled first from DOS. This
22means you will have to load your socket and card services, and
23QL41DOS.SYS and QL40ENBL.SYS. These are a minimum, but loading the
24rest of the modules won't interfere with the operation. The next
25thing to do is load the kernel without resetting the hardware, which
26can be a simple ctrl-alt-delete with a boot floppy, or by using
27loadlin with the kernel image accessible from DOS. If you are using
28the Linux PCMCIA driver, you will have to adjust it or otherwise stop
29it from configuring the card.
30
31I am working with the PCMCIA group to make it more flexible, but that
32may take a while.
33
34ALL CARDS
35
36The top of the qlogic.c file has a number of defines that controls
37configuration. As shipped, it provides a balance between speed and
38function. If there are any problems, try setting SLOW_CABLE to 1, and
39then try changing USE_IRQ and TURBO_PDMA to zero. If you are familiar
40with SCSI, there are other settings which can tune the bus.
41
42It may be a good idea to enable RESET_AT_START, especially if the
43devices may not have been just powered up, or if you are restarting
44after a crash, since they may be busy trying to complete the last
45command or something. It comes up faster if this is set to zero, and
46if you have reliable hardware and connections it may be more useful to
47not reset things.
48
49SOME TROUBLESHOOTING TIPS
50
51Make sure it works properly under DOS. You should also do an initial FDISK
52on a new drive if you want partitions.
53
54Don't enable all the speedups first. If anything is wrong, they will make
55any problem worse.
56
57IMPORTANT
58
59The best way to test if your cables, termination, etc. are good is to
60copy a very big file (e.g. a doublespace container file, or a very
61large executable or archive). It should be at least 5 megabytes, but
62you can do multiple tests on smaller files. Then do a COMP to verify
63that the file copied properly. (Turn off all caching when doing these
64tests, otherwise you will test your RAM and not the files). Then do
6510 COMPs, comparing the same file on the SCSI hard drive, i.e. "COMP
66realbig.doc realbig.doc". Then do it after the computer gets warm.
67
68I noticed my system which seems to work 100% would fail this test if
69the computer was left on for a few hours. It was worse with longer
70cables, and more devices on the SCSI bus. What seems to happen is
71that it gets a false ACK causing an extra byte to be inserted into the
72stream (and this is not detected). This can be caused by bad
73termination (the ACK can be reflected), or by noise when the chips
74work less well because of the heat, or when cables get too long for
75the speed.
76
77Remember, if it doesn't work under DOS, it probably won't work under
78Linux.
79

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