Re: 2.1.115 scsi funnies

Richard Waltham (dormouse@farsrobt.demon.co.uk)
Mon, 10 Aug 1998 20:18:20 +0100 (BST)


Ville Voutilainen wrote:
>
> Howdy people, I have noticed some scsi peculiarities;
> my ncr53c810 claims that it does not support synchronous
> transfers, but AFAIK it does.
>
> --clip--
>
> >From /proc/scsi/ncr53c8xx/0:
>
> Chip NCR53C810a, device id 0x1, revision id 0x12
> IO port address 0xe000, IRQ number 11
> Using memory mapped IO at virtual address 0xc4800000
> Synchronous period factor 25, max commands per lun 32
>
> >From log:
>
> ncr53c810a-0-<4,*>: SYNC transfers not supported.
> --clip--
>
> Aren't these controversial? Inside /proc I can see a

Contradictory? ^^^^^^^ No. They refer to different things.

> sync period factor of 25, which should produce 10Mhz
> as sync frequency, which seems quite appropriate. Then

/proc/scsi/ncr53c8xx/0 give details on the controller and its capabilities.
It does not refer to any devices. This is what the controller is capable of.

> again at driver init (at boot) the kernel claims that
> SYNC transfers are not supported.

This is what the device the controller has found is capable of.
Target 4, whatever it is, is not capable of synchronous transfers.

>
> Then another thing; I tried ide-scsi for my ATAPI cdrom
> and when 'probe all luns on scsi devices' was enabled,
> the cdrom got detected 8 times, on every possible lun.

Something funny with ide-scsi may be, or may be the drive. Some real SCSI
devices will report more than one lun even though they only have one. That
is generally caused by a bug in the SCSI device firmware.

My two real SCSI jukeboxes behave just fine.

> Now, it's easy to get around this by disabling the probe
> option, but what if I had a CD jukebox _and_ I wanted to
> use ide-scsi? It is probably harmless that the drive gets
> detected 8 times, but it is just annoying if it can be
> avoided. Boot parameters, anyone?
>

Sorry can't help with this.

Richard

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-- 
 Richard Waltham   |              Work: richard@digitalinterface.demon.co.uk
   At home in      |              Home:        dormouse@farsrobt.demon.co.uk
 Southampton UK    |                              100421.1276@compuserve.com

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