MFI and passthrough

[Doug Ambrisko]

Scott Long writes:
| The passthrough interface is really only meant for doing management
| tasks like SMART monitoring and firmware flashes.  I've also seen it
| used for low-duty devices like tape drives.  I do not recommend using it
| to directly control disks in a primary fashion.  However, since this is
| open source, I won't prevent you from trying =-)  Try the following
| patch:
| 
| --- mfi_cam.c   12 Oct 2007 16:52:55 -0000      1.3
| +++ mfi_cam.c   31 Oct 2007 03:42:25 -0000
| @@ -344,9 +344,11 @@
|                          command = ccb->csio.cdb_io.cdb_bytes[0];
|                  if (command == INQUIRY) {
|                          device = ccb->csio.data_ptr[0] & 0x1f;
| +#if 0
|                          if ((device == T_DIRECT) || (device == 
| T_PROCESSOR))
|                                  csio->data_ptr[0] =
|                                       (device & 0xe0) | T_NODEVICE;
| +#endif
|                  }
|                  break;
|          }

BTW, it works great in this mode if you know what you are doing :-)

| I do believe that Dell does sell a direct attached disk option for
| the 2950/1950 called the PERC5/e.  It's essentially an LSI MPT-SAS
| controller that directly replaces the PERC5/i card that you have now.
| It should be able to control all 6 disk slots, and can do both SAS
| and SATA.

I've been told the PERC5/e and PERC5/i are the same except for PCI
sub-device ID and are both the mfi(4) RAID controllers.  They do
have a mpt(4) based card but it only supports 4 bays.  I'm not sure
what it's real name is but we have some lying around for random
testing.  I don't leave them in machines.

Doug A.