README file for the dc395x SCSI driver


The driver has been tested with CD-R and CD-R/W drives. These should be safe to use. Testing with hard disks has not been done to any great degree and caution should be exercised if you want to attempt to use this driver with hard disks.

This is a 2.5 only driver. For a 2.4 driver please see the original driver (which this driver started from) at

Problems, questions and patches should be submitted to the mailing list. Details on the list, including archives, are available at


The driver uses the settings from the EEPROM set in the SCSI BIOS setup. If there is no EEPROM, the driver uses default values. Both can be overridden by command line parameters (module or kernel parameters).

The following parameters are available:


Default: 0, Acceptable values: 0 or 1

If safe is set to 1 then the adapter will use conservative (“safe”) default settings. This sets:

shortcut for dc395x=7,4,9,15,2,10

Default: 7, Acceptable values: 0 to 15

Sets the host adapter SCSI ID.


Default: 1, Acceptable value: 0 to 7

0 20 Mhz
1 12.2 Mhz
2 10 Mhz
3 8 Mhz
4 6.7 Mhz
5 5.8 Hhz
6 5 Mhz
7 4 Mhz

Bitmap for device configuration

DevMode bit definition:

Bit Val(hex) Val(dec) Meaning
0 0x01 1 Parity check
1 0x02 2 Synchronous Negotiation
2 0x04 4 Disconnection
3 0x08 8 Send Start command on startup. (Not used)
4 0x10 16 Tagged Command Queueing
5 0x20 32 Wide Negotiation

Bitmap for adapter configuration

AdaptMode bit definition

Bit Val(hex) Val(dec) Meaning
0 0x01 1 Support more than two drives. (Not used)
1 0x02 2 Use DOS compatible mapping for HDs greater than 1GB.
2 0x04 4 Reset SCSI Bus on startup.
3 0x08 8 Active Negation: Improves SCSI Bus noise immunity.
4 0x10 16 Immediate return on BIOS seek command. (Not used)
(*)5 0x20 32 Check for LUNs >= 1.

Default: 3, Acceptable values: 0-5

The number of tags is 1<<x, if x has been specified


Default: 1, Acceptable values: 0-180

The seconds to not accept commands after a SCSI Reset

For the built in driver the parameters should be prefixed with dc395x. (eg “”)