Documentation/scsi/in2000.txt

   1
   2 UPDATE NEWS: version 1.33 - 26 Aug 98
   3
   4    Interrupt management in this driver has become, over
   5    time, increasingly odd and difficult to explain - this
   6    has been mostly due to my own mental inadequacies. In
   7    recent kernels, it has failed to function at all when
   8    compiled for SMP. I've fixed that problem, and after
   9    taking a fresh look at interrupts in general, greatly
  10    reduced the number of places where they're fiddled
  11    with. Done some heavy testing and it looks very good.
  12    The driver now makes use of the __initfunc() and
  13    __initdata macros to save about 4k of kernel memory.
  14    Once again, the same code works for both 2.0.xx and
  15    2.1.xx kernels.
  16
  17 UPDATE NEWS: version 1.32 - 28 Mar 98
  18
  19    Removed the check for legal IN2000 hardware versions:
  20    It appears that the driver works fine with serial
  21    EPROMs (the 8-pin chip that defines hardware rev) as
  22    old as 2.1, so we'll assume that all cards are OK.
  23
  24 UPDATE NEWS: version 1.31 - 6 Jul 97
  25
  26    Fixed a bug that caused incorrect SCSI status bytes to be
  27    returned from commands sent to LUNs greater than 0. This
  28    means that CDROM changers work now! Fixed a bug in the
  29    handling of command-line arguments when loaded as a module.
  30    Also put all the header data in in2000.h where it belongs.
  31    There are no longer any differences between this driver in
  32    the 2.1.xx source tree and the 2.0.xx tree, as of 2.0.31
  33    and 2.1.45 (or is it .46?) - this makes things much easier
  34    for me...
  35
  36 UPDATE NEWS: version 1.30 - 14 Oct 96
  37
  38    Fixed a bug in the code that sets the transfer direction
  39    bit (DESTID_DPD in the WD_DESTINATION_ID register). There
  40    are quite a few SCSI commands that do a write-to-device;
  41    now we deal with all of them correctly. Thanks to Joerg
  42    Dorchain for catching this one.
  43
  44 UPDATE NEWS: version 1.29 - 24 Sep 96
  45
  46    The memory-mapped hardware on the card is now accessed via
  47    the 'readb()' and 'readl()' macros - required by the new
  48    memory management scheme in the 2.1.x kernel series.
  49    As suggested by Andries Brouwer, 'bios_param()' no longer
  50    forces an artificial 1023 track limit on drives. Also
  51    removed some kludge-code left over from struggles with
  52    older (buggy) compilers.
  53
  54 UPDATE NEWS: version 1.28 - 07 May 96
  55
  56    Tightened up the "interrupts enabled/disabled" discipline
  57    in 'in2000_queuecommand()' and maybe 1 or 2 other places.
  58    I _think_ it may have been a little too lax, causing an
  59    occasional crash during full moon. A fully functional
  60    /proc interface is now in place - if you want to play
  61    with it, start by doing 'cat /proc/scsi/in2000/0'. You
  62    can also use it to change a few run-time parameters on
  63    the fly, but it's mostly for debugging. The curious
  64    should take a good look at 'in2000_proc_info()' in the
  65    in2000.c file to get an understanding of what it's all
  66    about; I figure that people who are really into it will
  67    want to add features suited to their own needs...
  68    Also, sync is now DISABLED by default.
  69
  70 UPDATE NEWS: version 1.27 - 10 Apr 96
  71
  72    Fixed a well-hidden bug in the adaptive-disconnect code
  73    that would show up every now and then during extreme
  74    heavy loads involving 2 or more simultaneously active
  75    devices. Thanks to Joe Mack for keeping my nose to the
  76    grindstone on this one.
  77
  78 UPDATE NEWS: version 1.26 - 07 Mar 96
  79
  80    1.25 had a nasty bug that bit people with swap partitions
  81    and tape drives. Also, in my attempt to guess my way
  82    through Intel assembly language, I made an error in the
  83    inline code for IO writes. Made a few other changes and
  84    repairs - this version (fingers crossed) should work well.
  85
  86 UPDATE NEWS: version 1.25 - 05 Mar 96
  87
  88    Kernel 1.3.70 interrupt mods added; old kernels still OK.
  89    Big help from Bill Earnest and David Willmore on speed
  90    testing and optimizing: I think there's a real improvement
  91    in this area.
  92    New! User-friendly command-line interface for LILO and
  93    module loading - the old method is gone, so you'll need
  94    to read the comments for 'setup_strings' near the top
  95    of in2000.c. For people with CDROM's or other devices
  96    that have a tough time with sync negotiation, you can
  97    now selectively disable sync on individual devices -
  98    search for the 'nosync' keyword in the command-line
  99    comments. Some of you disable the BIOS on the card, which
 100    caused the auto-detect function to fail; there is now a
 101    command-line option to force detection of a ROM-less card.
 102
 103 UPDATE NEWS: version 1.24a - 24 Feb 96
 104
 105    There was a bug in the synchronous transfer code. Only
 106    a few people downloaded before I caught it - could have
 107    been worse.
 108
 109 UPDATE NEWS: version 1.24 - 23 Feb 96
 110
 111    Lots of good changes. Advice from Bill Earnest resulted
 112    in much better detection of cards, more efficient usage
 113    of the fifo, and (hopefully) faster data transfers. The
 114    jury is still out on speed - I hope it's improved some.
 115    One nifty new feature is a cool way of doing disconnect/
 116    reselect. The driver defaults to what I'm calling
 117    'adaptive disconnect' - meaning that each command is
 118    evaluated individually as to whether or not it should be
 119    run with the option to disconnect/reselect (if the device
 120    chooses), or as a "SCSI-bus-hog". When several devices
 121    are operating simultaneously, disconnects are usually an
 122    advantage. In a single device system, or if only 1 device
 123    is being accessed, transfers usually go faster if disconnects
 124    are not allowed.
 125
 126
 127
 128 The default arguments (you get these when you don't give an 'in2000'
 129 command-line argument, or you give a blank argument) will cause
 130 the driver to do adaptive disconnect, synchronous transfers, and a
 131 minimum of debug messages. If you want to fool with the options,
 132 search for 'setup_strings' near the top of the in2000.c file and
 133 check the 'hostdata->args' section in in2000.h - but be warned! Not
 134 everything is working yet (some things will never work, probably).
 135 I believe that disabling disconnects (DIS_NEVER) will allow you
 136 to choose a LEVEL2 value higher than 'L2_BASIC', but I haven't
 137 spent a lot of time testing this. You might try 'ENABLE_CLUSTERING'
 138 to see what happens: my tests showed little difference either way.
 139 There's also a define called 'DEFAULT_SX_PER'; this sets the data
 140 transfer speed for the asynchronous mode. I've put it at 500 ns
 141 despite the fact that the card could handle settings of 376 or
 142 252, because higher speeds may be a problem with poor quality
 143 cables or improper termination; 500 ns is a compromise. You can
 144 choose your own default through the command-line with the
 145 'period' keyword.
 146
 147
 148 ------------------------------------------------
 149 ***********  DIP switch settings  **************
 150 ------------------------------------------------
 151
 152    sw1-1 sw1-2    BIOS address (hex)
 153    -----------------------------------------
 154     off   off     C8000 - CBFF0
 155     on    off     D8000 - DBFF0
 156     off   on      D0000 - D3FF0
 157     on    on      BIOS disabled
 158
 159    sw1-3 sw1-4    IO port address (hex)
 160    ------------------------------------
 161     off   off     220 - 22F
 162     on    off     200 - 20F
 163     off   on      110 - 11F
 164     on    on      100 - 10F
 165
 166    sw1-5 sw1-6 sw1-7    Interrupt
 167    ------------------------------
 168     off   off   off     15
 169     off   on    off     14
 170     off   off   on      11
 171     off   on    on      10
 172     on    -     -       disabled
 173
 174    sw1-8 function depends on BIOS version. In earlier versions this
 175    controlled synchronous data transfer support for MSDOS:
 176       off = disabled
 177       on  = enabled
 178    In later ROMs (starting with 01.3 in April 1994) sw1-8 controls
 179    the "greater than 2 disk drive" feature that first appeared in
 180    MSDOS 5.0 (ignored by Linux):
 181       off = 2 drives maximum
 182       on  = 7 drives maximum
 183
 184    sw1-9    Floppy controller
 185    --------------------------
 186     off     disabled
 187     on      enabled
 188
 189 ------------------------------------------------
 190
 191    I should mention that Drew Eckhardt's 'Generic NCR5380' sources
 192    were my main inspiration, with lots of reference to the IN2000
 193    driver currently distributed in the kernel source. I also owe
 194    much to a driver written by Hamish Macdonald for Linux-m68k(!).
 195    And to Eric Wright for being an ALPHA guinea pig. And to Bill
 196    Earnest for 2 tons of great input and information. And to David
 197    Willmore for extensive 'bonnie' testing. And to Joe Mack for
 198    continual testing and feedback.
 199
 200
 201             John Shifflett    jshiffle@netcom.com
 202