To SCSI driver maintainers: 16-byte CDB support in SCSI interface

Khalid Aziz (khalid@fc.hp.com)
Mon, 29 Oct 2001 12:57:39 -0700


ac series kernels starting with 2.4.10-ac5 contain a patch that enables
SCSI midlayer to send SCSI commands larger than 12 bytes to the
interface
drivers. Before sending a larger command, midlayer will check the
command size against Scsi_Host->max_cmd_len. If Scsi_Host->max_cmd_len
is larger than or equal to the command size, the command will be sent
to the interface driver else it will be terminated with an error.
scsi_register() sets Scsi_Host->max_cmd_len to 12 by default for every
interface. If a driver and the interface can support larger commands,
the driver should set Scsi_Host->max_cmd_len to the correct value after
calling scsi_register(). Please make this change to your driver if you
would like to support larger SCSI commands. Non-ac kernels will not
be affected by this change since Scsi_Host->max_cmd_len is unused on
those kernels.

-- 
Khalid

==================================================================== Khalid Aziz Linux Systems Operation R&D (970)898-9214 Hewlett-Packard khalid@fc.hp.com Fort Collins, CO - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/