> Hi,
>
> I have a question on the ncr53c8xx driver. I have one ncr53c895
> and one ncr53c810a. I have 2 LVD drives on ncr53c895. For some
> reason, they are set as FAST-20, not Fast-40 as I expected. The
> BIOS sees them as 80MB/s. Is there the bug in the driver? Should
> I try to take out ncr53c810a?
>From driver point of view, the instance of the 895 has no relationship
with the 810a one. A bug is always possible, but I doubt the problem would
be due to a bug.
LVD devices are in fact LVD/SE devices.
LVD = low-voltage-differential (FAST40 a.k.a. Ultra2)
SE = single-ended (FAST20 a.k.a. Ultra)
All the devices on the SCSI BUS are sensing the DIFFSENS signal level and
will switch to SE mode if this signal indicates that at least 1 device on
the SCSI BUS is operating in SE mode, then limiting data transfer speed to
FAST20.
So, in order to use LVD signaling and then to get 80 MB/s sync wide data
transfers on your SCSI BUS, you must ensure the following:
- All devices including the controller are LVD capable and configured for
this signaling (is such an option is possible).
- All terminators (2) are LVD capable or LVD/SE (same behaviour as
other devices).
- All the cables meet the requirements for LVD.
You also must:
- Configure the driver for 40 MHz sync data transferts. Or tell it so at
boot-up using 'ncr53c8xx=sync:10', if the driver has been configured for
slower sync data transfers.
- Configure your LVD devices for 80 MB/s data transfers in the SYMBIOS
user set-up (NVRAM).
It seems that LVD drive internal terminations are not LVD/SE but only SE.
So, if any drive has its SE internal terminator enabled, then all the
devices on the SCSI BUS will switch to SE mode, and the SCSI BUS will
operate in FAST20 mode.
Hope this will help.
Regards,
Gérard.
PS: the driver should probably print out the SCSI mode which is currently
operating on the BUS. I will add such a message in the next drivers'
versions.
> Thanks.
>
>
> H.J.
> ---
> ncr53c8xx: at PCI bus 0, device 15, function 0
> ncr53c8xx: 53c810a detected
> ncr53c8xx: at PCI bus 0, device 16, function 0
> ncr53c8xx: 53c895 detected with Symbios NVRAM
> ncr53c895-0: rev=0x02, base=0xf4201400, io_port=0x1400, irq=19
> ncr53c895-0: Symbios format NVRAM, ID 7, Fast-40, Parity Checking
> ncr53c895-0: initial SCNTL3/DMODE/DCNTL/CTEST3/4/5 = (hex) 07/4e/a0/01/00/24
> ncr53c895-0: final SCNTL3/DMODE/DCNTL/CTEST3/4/5 = (hex) 07/8e/a0/00/08/24
> ncr53c895-0: on-chip RAM at 0xf4200000
> ncr53c895-0: resetting, command processing suspended for 2 seconds
> ncr53c895-0: restart (scsi reset).
> ncr53c895-0: enabling clock multiplier
> ncr53c895-0: Downloading SCSI SCRIPTS.
> ncr53c810a-1: rev=0x12, base=0xf4201000, io_port=0x1000, irq=18
> ncr53c810a-1: ID 7, Fast-10, Parity Checking
> ncr53c810a-1: restart (scsi reset).
> scsi0 : ncr53c8xx - revision 3.1h
> scsi1 : ncr53c8xx - revision 3.1h
> scsi : 2 hosts.
> ncr53c895-0: command processing resumed
> Vendor: QUANTUM Model: VIKING II 4.5WLS Rev: 5520
> Type: Direct-Access ANSI SCSI revision: 02
> Detected scsi disk sda at scsi0, channel 0, id 0, lun 0
> Vendor: QUANTUM Model: QM318000TD-SW Rev: N491
> Type: Direct-Access ANSI SCSI revision: 02
> Detected scsi disk sdb at scsi0, channel 0, id 1, lun 0
> ncr53c895-0-<0,0>: tagged command queue depth set to 8
> ncr53c895-0-<1,0>: tagged command queue depth set to 8
> Vendor: MICROP Model: 4110-09NB_Nov18F Rev: TN0F
> Type: Direct-Access ANSI SCSI revision: 02
> Detected scsi disk sdc at scsi1, channel 0, id 0, lun 0
> Vendor: HP Model: C3725S Rev: 6039
> Type: Direct-Access ANSI SCSI revision: 02
> Detected scsi disk sdd at scsi1, channel 0, id 1, lun 0
> ncr53c810a-1-<1,0>: tagged command queue depth set to 8
> scsi : detected 4 SCSI disks total.
> ncr53c895-0-<0,*>: WIDE SCSI (16 bit) enabled.
> ncr53c895-0-<0,*>: FAST-20 WIDE SCSI 40.0 MB/s (50 ns, offset 31)
> SCSI device sda: hdwr sector= 512 bytes. Sectors= 8910423 [4350 MB] [4.4 GB]
> ncr53c895-0-<1,*>: WIDE SCSI (16 bit) enabled.
> ncr53c895-0-<1,*>: FAST-20 WIDE SCSI 40.0 MB/s (50 ns, offset 31)
> SCSI device sdb: hdwr sector= 512 bytes. Sectors= 35566500 [17366 MB] [17.4 GB]
> ncr53c810a-1-<0,*>: FAST-10 SCSI 10.0 MB/s (100 ns, offset 8)
> SCSI device sdc: hdwr sector= 512 bytes. Sectors= 2053880 [1002 MB] [1.0 GB]
> ncr53c810a-1-<1,*>: FAST-10 SCSI 10.0 MB/s (100 ns, offset 8)
> SCSI device sdd: hdwr sector= 512 bytes. Sectors= 4194058 [2047 MB] [2.0 GB]
> Partition check:
> sda: sda1 sda2 sda3 sda4 < sda5 sda6 sda7 sda8 >
> sdb: sdb1 sdb2 sdb3 sdb4
> sdc: sdc1
> sdd:Dev 08:30 Sun disklabel: bad magic 0000
> unknown partition table
>
>
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