[lug] scsi drive, mmap and bus errors

[Bear Giles]

Some more information on this... definitely starting to look like
a hardware problem.

1) if I scan the compressed tarball sequentially, and decompress
   the file 'as a whole,' I almost always lock up the system.  Not
   just a 'bus error' - a hard system lock.

2) If I decompress the file in up to 512 byte chunks into a memory
   buffer, I lock up the system.  I get further into the tarball 
   than above, but that's cold comfort.

3) If I decompress the file in up to 512 byte chunks into a 
   memory-mapped output file, everything is fine.

The only difference between the last two items is that the latter
has a bit more overhead because it has to flush the memory buffer
to disk.


SCSI information (immediately after reboot, which is why numbers are
zero):

/proc/scsi/aic7xxx/0
--------------------

Adaptec AIC7xxx driver version: 5.1.28/3.2.4
Compile Options:
  TCQ Enabled By Default : Disabled
  AIC7XXX_PROC_STATS     : Enabled
  AIC7XXX_RESET_DELAY    : 5

Adapter Configuration:
           SCSI Adapter: Adaptec AIC-7860 Ultra SCSI host adapter
                           Ultra Narrow Controller at PCI 0/12/0
    PCI MMAPed I/O Base: 0xdb800000
 Adapter SEEPROM Config: SEEPROM found and used.
      Adaptec SCSI BIOS: Enabled
                    IRQ: 11
                   SCBs: Active 0, Max Active 1,
                         Allocated 15, HW 3, Page 255
             Interrupts: 66
      BIOS Control Word: 0x10b6
   Adapter Control Word: 0x0059
   Extended Translation: Enabled
Disconnect Enable Flags: 0x00ff
     Ultra Enable Flags: 0x0000
 Tag Queue Enable Flags: 0x0000
Ordered Queue Tag Flags: 0x0000
Default Tag Queue Depth: 8
    Tagged Queue By Device array for aic7xxx host instance 0:
      {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255}
    Actual queue depth per device for aic7xxx host instance 0:
      {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1}

Statistics:

(scsi0:0:2:0)
  Device using Narrow/Sync transfers at 10.0 MByte/sec, offset 15
  Transinfo settings: current(25/15/0/0), goal(25/15/0/0), user(25/15/0/0)
  Total transfers 0 (0 reads and 0 writes)
             < 2K      2K+     4K+     8K+    16K+    32K+    64K+   128K+
   Reads:       0       0       0       0       0       0       0       0
  Writes:       0       0       0       0       0       0       0       0


(scsi0:0:5:0)
  Device using Narrow/Sync transfers at 10.0 MByte/sec, offset 15
  Transinfo settings: current(25/15/0/0), goal(25/15/0/0), user(25/15/0/0)
  Total transfers 0 (0 reads and 0 writes)
             < 2K      2K+     4K+     8K+    16K+    32K+    64K+   128K+
   Reads:       0       0       0       0       0       0       0       0
  Writes:       0       0       0       0       0       0       0       0


/proc/scsi/scsi
---------------

Attached devices: 
Host: scsi0 Channel: 00 Id: 02 Lun: 00
  Vendor: TOSHIBA  Model: CD-ROM XM-6401TA Rev: 1009
  Type:   CD-ROM                           ANSI SCSI revision: 02
Host: scsi0 Channel: 00 Id: 05 Lun: 00
  Vendor: YAMAHA   Model: CRW6416S         Rev: 1.0c
  Type:   CD-ROM                           ANSI SCSI revision: 02

The CD-ROM is internal, the CD-RW is external.