PCI edge or level trigger?

PCI edge or level trigger?

Post by Laurence Lundblad » Sun, 28 May 1995 04:00:00

I'm trying to figure out what's correct, edge or level trigger for my NCR
53C810 on my ASUS PCI/I-486SP3G mother board.  The BIOS set up screens
don't allow me to change this for the NCR chip (though it does for the
other PCI devices).  When I install the jumper to set the IRQ for edge
triggering it hangs.  I believe when it is working it is using level

The thing that doesn't make sense is that with the 1.2.5 kernel it
reported it was using level trigger which I think it correct.  With
the 1.2.8 kernel the messages are reversed and it says it is edge
triggered which I think is incorrect.  I'm not sure this makes any
difference as long as it interrupts.  Is that true?  Which is really
correct, the 1.2.5 kernel or the 1.2.8.

Also, another question which worries me more is whether or not the
stuff at the end indicated a bad disk drive or configuration/software
error.  I think it is a bad drive (it's brand new and so is my use of
PCI SCSI), but confirmation would be helpful.


Laurence Lundblade                            

        *ia Tech CS -- Blacksburg, *ia, US -- 703-552-2537

---- The start up ----
kernel: scsi0 : tests complete.
kernel: scsi0 : NCR53c{7,8}xx (rel 3)
kernel: scsi : 1 host.
kernel:   Vendor: MAXTOR    Model: MXT-540SL         Rev: H1.2
kernel:   Type:   Direct-Access                      ANSI SCSI revision: 02
kernel: Detected scsi disk sda at scsi0, id 1, lun 0
kernel: scsi : detected 1 SCSI disk total.
kernel: SCSI Hardware sector size is 512 bytes on device sda

--- The errors being logged ---
kernel: scsi0 : DMA FIFO not empty
kernel: scsi0 : DMA FIFO not empty
kernel: SCSI disk error : host 0 id 1 lun 0 return code = 28000000
kernel: Current error sd802: sense key Hardware Error
kernel: Additional sense indicates Peripheral device write fault
kernel: scsidisk I/O error: dev 0802, sector 254
kernel: scsi0 : DMA FIFO not empty
kernel: scsi0 : DMA FIFO not empty


1. Intel Plato Premiere PCI/II and edge/level triggered IRQs

I have problem with SCSI timeouts under FreeBSD 2.0
SNAP950412 in a system composed basically of an
Intel Plato P90 Premier PCI II (Neptune chipset)
and a PCI Adaptec 2940.

For what I read until now under freebsd,linux groups
seems that the MB I'm testing use edge-triggered IRQ
rather than level-sensitive on the PCI bus.

This is confirmed too from an online manual for
this board I found on gatekeeper.dec.com. It claims
that the version of BIOS I use now setup the card for edge-triggerd IRQ.
This was not true evidentily for previous versions.

This seems confirmed too from the fact that using
FreeBSD-current aix7xxxx drivers (that use by default
edge-trigger IRQS) the system behave correctly.


  (1) Anyone may confirm this is correct for this
      particular MB?

  (2) Are there any way to setup the MB for use
      level-sensitive IRQS?

  (3) In the case answer to question (2) is "impossible"
      it would be "safe" to buy a mother in this conditions?

E-mail answers are preferred, Thanks, Peppe.

University of Perugia Italy         |  06124 Perugia  Phone:+39.75.585-2799
All comments/opinions are mine and don't represent those of IBM

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