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Documentation / scsi / dtc3x80.txt




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Based on kernel version 3.16. Page generated on 2014-08-06 21:41 EST.

1	README file for the Linux DTC3180/3280 scsi driver.
2	by Ray Van Tassle (rayvt@comm.mot.com)  March 1996
3	Based on the generic & core NCR5380 code by Drew Eckhard
4	
5	SCSI device driver for the DTC 3180/3280.
6	Data Technology Corp---a division of Qume.
7	
8	The 3280 has a standard floppy interface.
9	
10	The 3180 does not.  Otherwise, they are identical.
11	
12	The DTC3x80 does not support DMA but it does have Pseudo-DMA which is
13	supported by the driver.
14	
15	Its DTC406 scsi chip is supposedly compatible with the NCR 53C400.
16	It is memory mapped, uses an IRQ, but no dma or io-port.  There is
17	internal DMA, between SCSI bus and an on-chip 128-byte buffer.  Double
18	buffering is done automagically by the chip.  Data is transferred
19	between the on-chip buffer and CPU/RAM via memory moves.
20	
21	The driver detects the possible memory addresses (jumper selectable):
22		CC00, DC00, C800, and D800
23	The possible IRQ's (jumper selectable) are:
24		IRQ 10, 11, 12, 15
25	Parity is supported by the chip, but not by this driver.
26	Information can be obtained from /proc/scsi/dtc3c80/N.
27	
28	Note on interrupts:
29	
30	The documentation says that it can be set to interrupt whenever the
31	on-chip buffer needs CPU attention.  I couldn't get this to work.  So
32	the driver polls for data-ready in the pseudo-DMA transfer routine.
33	The interrupt support routines in the NCR3280.c core modules handle
34	scsi disconnect/reconnect, and this (mostly) works.  However.....  I
35	have tested it with 4 totally different hard drives (both SCSI-1 and
36	SCSI-2), and one CDROM drive.  Interrupts works great for all but one
37	specific hard drive.  For this one, the driver will eventually hang in
38	the transfer state.  I have tested with: "dd bs=4k count=2k
39	of=/dev/null if=/dev/sdb".  It reads ok for a while, then hangs.
40	After beating my head against this for a couple of weeks, getting
41	nowhere, I give up.  So.....This driver does NOT use interrupts, even
42	if you have the card jumpered to an IRQ.  Probably nobody will ever
43	care.
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